Atherogenic dyslipidemia in HIV-infected individuals treated with protease inhibitors. The Swiss HIV Cohort Study.

BACKGROUND: Administration of protease inhibitors (PIs) to HIV-infected individuals has been associated with hyperlipidemia. In this study, we characterized the lipoprotein profile in subjects receiving ritonavir, indinavir, or nelfinavir, alone or in combination with saquinavir. METHODS AND RESULTS: Plasma lipoprotein levels were quantified in 93 HIV-infected adults receiving PIs. Comparison was done with pretreatment values and with 28 nonPI-treated HIV-infected subjects. An elevation in plasma cholesterol levels was observed in all PI-treated groups but was more pronounced for ritonavir (2.0+/-0.3 mmol/L [mean+/-SEM], n=46, versus 0.1+/-0.2 mmol/L in nonPI treated group, P<0.001) than for indinavir (0.8+/-0.2 mmol/L, n=26, P=0.03) or nelfinavir (1.2+/-0.2 mmol/L, n=21, P=0.01). Administration of ritonavir, but not indinavir or nelfinavir, was associated with a marked elevation in plasma triglyceride levels (1.83+/-0.46 mmol/L, P=0.002). Plasma HDL-cholesterol levels remained unchanged. Combination of ritonavir or nelfinavir with saquinavir did not further elevate plasma lipid levels. A 48% increase in plasma levels of lipoprotein(a) was detected in PI-treated subjects with pretreatment Lp(a) values >20 mg/dL. Similar changes in plasma lipid levels were observed in 6 children receiving ritonavir. CONCLUSIONS: Administration of PIs to HIV-infected individuals is associated with a marked, compound-specific dyslipidemia. The risk of pancreatitis and premature atherosclerosis due to PI-associated dyslipidemia remains to be established.

Functional and morphological changes in mediobasal hypothalamus of streptozocin-induced diabetic rats. In vitro study of LHRH release.

To investigate the role of the mediobasal hypothalamus (MBH) in diabetic gonadal axis disorders, the MBHs of adult male streptozocin-induced diabetic (STZ-D) rats were examined after incubation in basal conditions or in K+-enriched medium and compared with those of controls. Diabetes lasted 1 mo. Both luteinizing-hormone-releasing hormone (LHRH) release and MBH morphology were studied. After incubation in basal conditions, the LHRH release was unchanged. By light microscopy, the dilated-axon cross sections were more numerous (P less than .01) in the basal arcuate nucleus and in the median eminence. By electron microscopy, the ratio of exocytoses to neurosecretory granules observed in the median eminence axon cross sections was smaller (P less than .05). The total LHRH immunoreactivity, the number of labeled axons, and the amount of positive material in the axons were reduced (P less than .05). After incubation in K+-enriched medium, the LHRH release was markedly reduced (P less than .01). The number and area of dilated-axon cross sections, possibly because of the relation between exocytosis and physiological dilation, were less augmented (P less than .01). Whereas the number of exocytoses and the ratio of exocytoses to neurosecretory granules were not decreased, the total LHRH immunoreactivity and the number of labeled axons were reduced (P less than .05). The releasable LHRH pool therefore seems to be exhausted in control MBH because of long-term stimulation and reduced in the MBH of STZ-D rats because of diabetes. In conclusion, STZ-D causes functional and anatomical MBH lesions that should be pathogenetically relevant for the disorders of the gonadal axis documented in this animal model.

Functional and morphological aspects of impaired TRH release by mediobasal hypothalamus of STZ-induced diabetic rats.

Streptozocin-induced diabetes (STZ-D) in rats is associated with marked hypothyroidism characterized by functional impairment and structural lesions of the pituitary-thyroid axis. Degenerative axonal lesions, which can be prevented by insulin administration, have been reported in the mediobasal hypothalamus (MBH) of STZ-D rats. However, direct evidence connecting anatomic MBH lesions with functional impairment is still missing. We therefore performed a combined functional and morphological investigation in 4-mo-old STZ-D male rats (diabetes lasted 1 mo), applying an in vitro model to study in the same isolated MBH 1) the basal and depolarization-induced thyrotropin-releasing hormone (TRH) release during two successive incubations of 20 min each and 2) morphological and morphometric aspects, including distribution and amount (densitometric evaluation) of immunoreactive TRH in the incubated tissue. In basal conditions, TRH release was much lower in diabetic than control MBH during both incubations (P less than .01 vs. P less than .05). In depolarizing conditions, TRH release was increased during the second incubation in control (P less than .05) and during both incubations in diabetic (P less than .01) rats, the percentage increase of the TRH release due to ionic stimulation being much higher in diabetic than control animals (P less than .01). As determined by light-microscope morphometry, the total area of dilated-axon cross sections was larger in diabetic than control MBH under basal conditions (P less than .01), thus confirming degenerative axonopathy in diabetic rats. By densitometry determination, the amount of immunoreactive TRH was higher in stimulated diabetic MBH compared with both stimulated control and basal diabetic MBH (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Hypothalamic secretion of dopamine after inhibition of aromatic L-amino acid decarboxylase activity.

An accumulation of L-dihydroxyphenylalanine (DOPA) in the median eminence of female rats treated with 3-hydroxybenzylhydrazine (NSD 1015), and inhibitor of aromatic L-amino acid decarboxylase (DOPA decarboxylase) activity, was associated with a decreased concentration of dopamine in the median eminence and pronounced reduction in the release of dopamine into hypophysial portal blood. The amount of dopamine released during 1 h into hypophysial portal blood of vehicle-treated rats represented 18% of the amount of DOPA that accumulated in 1 h in the median eminence of rats treated with NSD 1015. The reduction in the concentration of dopamine in the plasma of blood from a single hypophysial portal vessel after the inhibition of DOPA decarboxylase activity was associated with a concomitant increase in the concentration of PRL in the plasma of arterial blood. In contrast to that of dopamine, the concentration of norepinephrine as well as the concentration of epinephrine in hypophysial portal plasma was the same or slightly greater in animals treated with NSD 1015 than in animals treated with the solvent vehicle. These findings are supportive of the view that the release of dopamine from the tuberoinfundibular neurons is highly dependent on the rate of conversion of DOPA to dopamine and that the rate of synthesis of DOPA is a major factor in the control of the rate of release of dopamine into hypophysial portal blood.

Evidence for alteration in the processing of dopamine in the anterior pituitary gland of aged rats: receptors and intracellular compartmentalization of dopamine.

Receptors for dopamine and the subcellular localization of dopamine in the anterior pituitary gland were studied in young cycling female rats and in aged, constant estrous female rats. Dopamine receptors were quantified in membrane preparations of anterior pituitary tissue using [3H] spiperone as the ligand. On the basis of saturation isotherms, it was calculated that the equilibrium dissociation constant (Kd) and binding capacity for [3H]spiperone binding to pituitary membranes from young rats were 34.2 pM and 82 fmol/mg protein, respectively. The relative binding capacity of membranes from aged rats was 35% greater than that of membranes from young rats. There was no difference in the Kd values in aged and young rats. When the relative binding of [3H]spiperone by anterior pituitary membranes from individual animals was quantified by incubation with a saturating concentration of the ligand, it was found that [3H]spiperone binding in aged rats was significantly greater than that in young rats. When the subcellular localization of dopamine in anterior pituitary tissue was examined by means of density gradient centrifugation, it was found that the subcellular distribution of dopamine in tissue of aged rats was quantitatively different from that in young rats. In young rats, a small amount of dopamine was associated with light particles, whereas a large amount of dopamine was associated with heavy particles, which cosedimented with PRL-containing granules. In aged rats, the amount of dopamine associated with light particles was 5 times that found in young rats, whereas the amount of dopamine associated with heavy particles was the same as that in young rats. We speculate that altered intracellular compartmentalization of dopamine, leading to a marked accumulation of dopamine in the light particles, is related to increased secretion of PRL in aged rats.

Dopamine in plasma of lateral and medial hypophysial portal vessels: evidence for regional variation in the release of hypothalamic dopamine into hypophysial portal blood.

The plasma concentrations of dopamine in blood from hypophysial portal vessels in various locations on the pituitary stalk were evaluated in diestrous rats. It was found that the mean concentration of dopamine in blood from lateral hypophysial portal vessels, which contain the venous effluent of the lateral median eminence, was significantly less (P less than 0.005) than that in blood from medial portal vessels, which contain the venous effluent of the medial median eminence [1.59 +/- (SE) 0.23 ng/ml vs. 3.12 +/- 0.48 ng/ml]. The mean plasma concentration of dopamine in blood of lateral portal vessels and of medial portal vessels was at least 20-40 times greater than that in arterial blood of these animals. It was calculated that the rate of release of hypothalamic dopamine was 174 +/- 38 pg/h into a medial portal vessel and 73 +/- 15 pg/h into a lateral portal vessel. The mean plasma concentration of norepinephrine or epinephrine in blood from a medial portal vessel was not different from that from a lateral portal vessel. To address the issue of whether the rate of release of dopamine into a medial portal vessel and into a lateral portal vessel was correlated with the rate of synthesis of dopamine in discrete regions of the median eminence, the concentration of L-dihydroxyphenylalanine (DOPA), the precursor of dopamine, was evaluated in lateral and medial segments of the median eminence of diestrous rats treated with 3-hydroxybenzylhydrazine, an inhibitor of DOPA decarboxylase activity. The concentration of DOPA was similar in the medial and lateral segments of the median eminence, suggesting that the rate of synthesis of dopamine did not account for the difference in the rate of release of dopamine into portal blood. The finding of different concentrations of dopamine in blood from various hypophysial portal vessels may be important in view of the heterogenous perfusion of the pars distalis with hypophysial portal blood. We suggest that topographic differences may exist in the release of PRL by cells of the pituitary gland as a consequence of uneven concentrations of dopamine in portal blood perfusing the lactotropes.

Estrogen alters the responsiveness of the anterior pituitary gland to the actions of dopamine on lysosomal enzyme activity and prolactin release.

The effects of dopamine on PRL secretion and lysosomal enzyme activity in anterior pituitary tissue from rats selected during various stages of the estrous cycle were examined under in vitro conditions. During the estrous cycle, there was a marked variation in the capacity of dopamine to stimulate the activity of the lysosomal enzyme beta-glucuronidase in the anterior pituitary gland. Moreover, this variation in the responsiveness of pituitary tissue to the stimulatory action of dopamine on beta-glucuronidase activity was accompanied by a similar variation in the responsiveness of the tissue to the inhibitory action of dopamine on PRL release. Anterior pituitary glands from diestrous rats were the most sensitive to the actions of dopamine on beta-glucuronidase activity and PRL release, whereas glands from estrous animals were the least sensitive. Ovariectomy on the day of diestrus prevented the decline in the responsiveness of the anterior lobe to the actions of dopamine normally seen 2 days later (on the presumptive day of estrus). On the other hand, when animals were treated with estradiol benzoate during the 2 days after ovariectomy, the responsiveness of the pituitary tissue to dopamine was markedly suppressed and was similar to that of tissue from estrous rats. When rats were treated with progesterone during the 2 days after ovariectomy, the responsiveness of the anterior lobe to dopamine was similar to that in ovariectomized controls. It is suggested that the decrease in the responsiveness of the anterior pituitary gland to the actions of dopamine on lysosomal enzyme activity and PRL release that occurs between diestrus and estrus is estrogen mediated. It is also suggested that the ability of estrogen to antagonize the inhibitory effect of dopamine on PRL release may be mediated through an estrogen-induced reduction in the capacity of dopamine to stimulate lysosomal enzyme activity in the anterior pituitary gland.

Tuberoinfundibular dopaminergic neurons and lactotropes in young and old female rats.

Aging in female rats is accompanied by several endocrine dysfunctions, such as reproductive decline associated with characteristic hyperprolactinemia, lactotrope hyperplasia, and functional impairment of hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons. The aim of this morphometrical, immunocytochemical, and densitometrical study was to gain a better anatomical knowledge of TIDA neurons and axons as well as of lactotropes in old female rats with (A) or without (NA) pituitary adenomas, compared with young animals. At the hypothalamic level, we found that tyrosine hydroxylase (TH)-labeled neurons in the arcuate nucleus were comparable in young and old NA yet their size and TH-content were increased in A animals. Also the TH-labeled median eminence axons did not differ significantly between young and old NA but were more numerous in the old A rats. Independently from adenomas, both number of prolactin (PRL)-labeled structures and content of immunoreactive PRL were increased in pituitaries of old rats, the plasma PRL levels, however, were high only in A. Our findings support the documented lactotrope hypertrophy and hyperplasia in old female rats and suggest that TIDA-neuron changes only occur in hyperprolactinemic animals carrier of adenomas.

Diagnosis, treatment, and outcome of pituitary tumors and other abnormal intrasellar masses. Retrospective analysis of 353 patients.

We reviewed the clinical features, essential laboratory data, pituitary imaging findings (computerized tomography and magnetic resonance imaging), management, and outcome of 353 consecutive patients with the presumptive diagnosis of pituitary tumor investigated from January 1984 through December 1997 at University Hospital, Lausanne, Switzerland. In 18 cases primary empty sella turcica was diagnosed, and in 13 cases of pseudacromegaly there were no endocrine abnormalities. The remaining 322 patients disclosed abnormal pituitary masses, including 275 pituitary adenomas, 18 craniopharyngiomas, 6 cases of primary pituitary hyperplasia, 6 intrasellar meningiomas, 6 cases of distant metastases, 4 intrasellar cysts, 2 chordomas, 1 primary lymphoma, and 1 astrocytoma. Biologic data and immunohistochemical analysis of the excised tissues demonstrated that prolactinomas and nonsecreting adenomas (NSAs) were the most frequent pituitary tumors (40% and 39%, respectively), followed by somatotropic adenomas with acromegaly (11%) and Cushing disease (6%). In contrast with the vast majority of NSAs, which significantly expressed glycoprotein hormones in tissue without secreting them, there was a small group of glycoprotein hormone-secreting adenomas (2%), which had a more severe clinical course after surgery. Thirty-eight pituitary masses were incidentally discovered, most of them NSAs. The expansion of pituitary adenomas into the right cavernous sinus was twice as frequent as to the left cavernous sinus. For the differential diagnosis of hyperprolactinemia, basal prolactin (PRL) levels above 85 micrograms/L, in the absence of renal failure and PRL-enhancing drugs, and a PRL increment of less than 30% after thyrotropin-releasing hormone (TRH) accurately ruled out functional hyperprolactinemia due to NSA, and were typical of prolactinomas. For screening and follow-up of acromegaly, basal growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels, as well as the paradoxical GH response to TRH (present in 2/3 acromegalic patients), could be used as convenient tools, but the most accurate test for diagnosis and prediction of outcome after therapy was GH (lack of) suppression during oral glucose tolerance test. In Cushing disease, single evening plasma cortisol was as good as the overnight dexamethasone suppression test for screening, and a combined dexamethasoneovine corticotropin-releasing hormone (oCRH) test was as accurate as the long dexamethasone suppression test to confirm the diagnosis. Bilateral inferior petrosal sinus catheterization coupled with oCRH test confirmed the pituitary origin of excess adrenocorticotropic hormone (ACTH) in all patients, including those with normal pituitary on magnetic resonance imaging (50% of the cases). However, this procedure failed to predict tumor localization correctly within the pituitary in 21% of patients. Pituitary cysts, meningiomas, and craniopharyngiomas with an intrasellar component were correctly diagnosed based on pituitary imaging in 75%, 67%, and 44% of cases, respectively. The remainder, as well as the cases of pituitary hyperplasia, metastases, and other less frequent pathologies, were initially diagnosed as NSAs or as masses of unknown nature. When surgery was indicated, pituitary adenomas and other intrasellar masses were operated on by the transsphenoidal route, with the exception of 100% of meningiomas, 83% of craniopharyngiomas, and 10% of NSAs, which were operated on by the transcranial route. Favorable late surgical outcome of prolactinomas could be predicted by a restored PRL response to TRH. However, dopamine agonist (DA) therapy, usually resulting in satisfactory control of PRL levels and in tumor shrinkage, progressively displaced surgery as primary treatment for prolactinomas throughout the study period. After full-term pregnancy, the size of prolactinoma decreased in 7 of 9 patients, and PRL was normal in 2. Surgery was the first treatment for NSAs, with a tumor rela

Effects of long-term food reduction on the hypothalamus-pituitary-thyroid axis in male and female rats.

The reduced thyroid activity during short-term starvation is associated with a lowered hypothalamic synthesis and secretion of TRH. However, little is known about the cause of the reduced thyroid function during prolonged malnutrition. We have therefore studied the effects of food reduction to one-third of normal (FR33) on the hypothalamus-pituitary-thyroid axis of male and female Wistar rats. After 3 weeks body weights of FR33 rats were almost 50% lower than those of controls. In both sexes, FR33 caused marked increases in serum corticosterone, and decreases in serum TSH, thyroxine (T4), free T4, tri-iodothyronine (T3) and free T3. While the free T3 fraction (FFT3) in serum decreased, the free T4 fraction (FFT4) tended to increase. Electrophoretic analysis indicated that decreased FFT3 was correlated with an increased thyroxine-binding globulin, while the increase in FFT4 seemed due to a decreased thyroxine-binding prealbumin binding capacity. Total RNA and proTRH mRNA in the hypothalamus were not affected by FR33. Median eminence and posterior pituitary TRH content tended to increase in FR33 rats, suggesting that hypothalamic TRH release is reduced in FR33 rats. Anterior pituitary TSH content was decreased by FR33 in both sexes, but pituitary TSH beta mRNA and TRH receptor status were not affected except for increased pituitary TSH beta mRNA in female FR33 rats. Although FR33 had no effect on pituitary weight, pituitary RNA and membrane protein content in FR33 rats were 50-70% lower than values in controls. In conclusion, prolonged food reduction suppresses the pituitary-thyroid axis in rats. In contrast to short-term food deprivation, the mechanism whereby serum TSH is suppressed does not appear to involve decreases in proTRH gene expression, but may include effects on pituitary mRNA translation. Our results further support the hypothesis that TSH release may be lowered by increased corticosterone secretion, although the mechanism of this effect may differ between acute starvation and prolonged food reduction.

Influence of sex and age on T3 receptors and T3 concentration in the pituitary gland of the rat: consequences on TSH secretion.

A reduced secretion of thyroid hormones with age has been documented in humans and animals with no substantial increase in TSH secretion, which may be indicative of an age-related impairment of the pituitary sensitivity to the negative control exerted by thyroid hormones. We have evaluated in rats the influence of sex and age on pituitary T3 nuclear receptors--known to be determinant in the regulation of TSH secretion--as well as on T3 concentration in the pituitary gland. As regards sex, the density of T3 receptors and the concentration of T3 in pituitary gland and plasma were greater in females than in males whereas pituitary and plasma TSH concentrations were less. As for age, the density of T3 receptors was greater in old male rats than in young ones with no changes in pituitary T3 and plasma TSH concentrations. In old female rats in contrast, there was no significant increase in T3 receptors but pituitary T3 was less and plasma TSH greater than in young female rats. In both sexes plasma thyroid hormones and pituitary TSH were reduced with age whereas TSH response to TRH was not altered. These results illustrate sex and age differences in pituitary T3 receptors and pituitary T3 concentration as well as in TSH secretion. In young animals of both sexes an inverse correlation is observed between the density of pituitary T3 receptors and plasma TSH. In contrast, in old animals the absence of this correlation is suggestive of an age-related impairment of T3 action on the thyrotrophs or of changes pertaining to other factors modulating TSH secretion.

Influence of selenium supplements on the post-traumatic alterations of the thyroid axis: a placebo-controlled trial.

OBJECTIVE: To investigate whether early selenium (Se) supplementation can modify the post-traumatic alterations of thyroid hormone metabolism, since the first week after trauma is characterised by low plasma Se and negative Se balances. DESIGN: Prospective, placebo-controlled randomised supplementation trial. SETTING: Surgical ICU in a tertiary university hospital. PATIENTS: Thirty-one critically ill trauma patients aged 42 +/- 16 years (mean +/- SD), with severe multiple injury (Injury Severity Score 30 +/- 7). INTERVENTION: Supplementation during the first 5 days after injury with either Se or placebo. The selenium group was further randomised to receive daily 500 microg Se, with or without 150 mg alpha-tocopherol (AT) and 13 mg zinc supplements. The placebo group received the vehicle. Circulating Se, AT, zinc, and thyroid hormones were determined on D0 (= day 0, admission), D1, D2, D5, D10, and D20. RESULTS: Plasma Se, low on D0, normalised from D1 in the selenium group; total T4 and T3 increased more and faster after D2 (P = 0.04 and 0.08), reverse T3 rising less between D0 and D2 (P = 0.05). CONCLUSIONS: Selenium supplements increased the circulating Se levels. Supplementation was associated with modest changes in thyroid hormones, with an earlier normalisation of T4 and reverse T3 plasma levels. The addition of AT and zinc did not produce any additional change.

An inhibitory role for morphine on the release of dopamine into hypophysial portal blood and on the synthesis of dopamine in tuberoinfundibular neurons.

The intracerebroventricular administration of morphine to ovariectomized rats resulted in a marked decrease in the concentration of dopamine in plasma of hypophysial portal blood. A 90% reduction in the rate of release of hypothalamic dopamine into hypophysial portal blood occurred during the 60 min following the intraventricular administration of 60 ng of morphine sulfate. A dose-related decrease in the rate of release of dopamine into the portal vasculature was observed between 7.5 ng and 60 ng of morphine sulfate. Regardless of the quantity of morphine sulfate (1-500 ng) given to the animals, the concentrations of norepinephrine and epinephrine in hypophysial portal plasma and femoral arterial plasma remained unchanged. The efficacy of morphine on the release of dopamine into hypophysial portal blood was not associated with an equal efficacy of the drug on the synthesis of dopamine in tuberoinfundibular neurons, as evaluated by the accumulation of dihydroxyphenylalanine (DOPA) in the median eminence of rats given 3-hydroxybenzylhydrazine (NSD 1015). No effect of morphine was observed on DOPA accumulation in the median eminence of NSD-treated rats that had received 50 ng of morphine sulfate intracerebroventricularly, and only a 50% reduction was observed in the accumulation of DOPA in the median eminence of rats given 500 ng of morphine sulfate. These findings are supportive of the view that morphine inhibits both the release and synthesis of dopamine but is more effective in inhibiting the release than synthesis of dopamine.

Dopaminergic neurons in the mediobasal hypothalamus of old rats: evidence for decreased affinity of tyrosine hydroxylase for substrate and cofactor.

The effect of aging on the activity of tyrosine hydroxylase (TH) and on the number of TH-positive perikarya in the hypothalamus was studied in old and young female rats. The activity of TH in the mediobasal hypothalamus (MBH) of old rats was significantly (P less than 0.025) less than that in young rats. In old rats, the Km of TH for tyrosine as well as cofactor, 6-methyl-5,6,7,8-tetrahydropterine (6MPH4), was markedly greater than the Km in young rats. The maximal velocity was only slightly reduced in old animals. Contiguous coronal sections of the brain of an old and a young female rat were immunocytochemically stained for TH, and the TH-positive perikarya in the hypothalamus were counted. In the circumventricular region, 6793 TH-positive perikarya were present in the young brain and 6632 in the old brain. In the arcuate region, 2868 and 2760 TH-positive perikarya were counted in the young and old brain, respectively. It is concluded that the reduced TH activity in the MBH of old rats is not a consequence of a reduction in the number of TH-positive perikarya in the arcuate or circumventricular regions of the hypothalamus but is due to a reduction in the affinity of TH for its substrate and cofactor.

Cytochrome P-450 activities in human and rat brain microsomes.

The role of cytochrome P450 in the metabolism of dextromethorphan, amitriptyline, midazolam, S-mephenytoin, citalopram, fluoxetine and sertraline was investigated in rat and human brain microsomes. Depending on the parameters, the limit of quantification using gas chromatography-mass spectrometry methods was between 1.6 and 20 pmol per incubation, which generally contained 1500 microg protein. Amitriptyline was shown to be demethylated to nortriptyline by both rat and human microsomes. Inhibition studies using ketoconazole, furafylline, sulfaphenazole, omeprazole and quinidine suggested that CYP3A4 is the isoform responsible for this reaction whereas CYP1A2, CYP2C9, CYP2C19 and CYP2D6 do not seem to be involved. This result was confirmed by using a monoclonal antibody against CYP3A4. Dextromethorphan was metabolized to dextrorphan in rat brain microsomes and was inhibited by quinidine and by a polyclonal antibody against CYP2D6. Only the addition of exogenous reductase allowed the measurement of this activity in human brain microsomes. Metabolites of the other substrates could not be detected, possibly due to an insufficiently sensitive method. It is concluded that cytochrome P450 activity in the brain is very low, but that psychotropic drugs could undergo a local cerebral metabolism which could have pharmacological and/or toxicological consequences.

Follicle-stimulating hormone bioactivity in idiopathic normogonadotropic oligoasthenozoospermia: double-blind trial with gonadotropin-releasing hormone.

OBJECTIVE: To identify, among patients with idiopathic normogonadotropic oligoasthenozoospermia, those with low bioactive follicle-stimulating hormone (FSH), possibly because of inadequate gonadotropin-releasing hormone (GnRH) pulsatility, whose bioactive FSH and sperm could be improved by GnRH treatment. DESIGN: Randomized, double-blind, placebo-controlled trial with intranasal (IN) GnRH, followed by open GnRH treatment. SETTING: Outpatient endocrinology clinic. PATIENTS: Twenty-eight infertile men with idiopathic normogonadotropic oligoasthenozoospermia. INTERVENTIONS: Gonadotropin-releasing hormone or placebo was self-administered IN every 2 hours. MAIN OUTCOME MEASURES: Serum immunoreactive and bioactive FSH and semen analyses. RESULTS: Ten men showed a low basal FSH bioactive/immunoreactive ratio, which increased in 5 of them under GnRH without parallel sperm modification. Sperm improvements were observed in 10 patients with no parallel evolution of FSH bioactive/immunoreactive ratio. Unpredicted by sperm changes, three pregnancies developed on placebo and 5 on GnRH. CONCLUSIONS: Low bioactive FSH was not the cause of idiopathic normogonadotropic oligoasthenozoospermia in our patients and could not predict response to GnRH. Pulsatile GnRH did not improve sperm beyond random fluctuations.

Pulsatile secretion of gonadotropins and prolactin during the follicular and luteal phases of the menstrual cycle: analysis of instantaneous secretion rate and secretory concomitance.

OBJECTIVE: To characterize the pulsatile secretions of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) during the menstrual cycle and to statistically evaluate their secretory concomitance. DESIGN: Pulsatility study performed during the midfollicular and midluteal phases of a same menstrual cycle, blood samples being collected every 10 minutes for 6 hours. SETTING: Participants investigated in the Division of Endocrinology, University Hospital. PARTICIPANTS: Nine healthy women (22 to 38 years) with regular menstrual cycles. MAIN OUTCOME MEASURES: Plasma LH, FSH, and PRL values were analyzed as raw and deconvoluted data, and the specific (nonrandom) secretory concomitance was evaluated statistically. RESULTS: The pulsatile secretion of LH was confirmed, and that of FSH and PRL was clearly established during both phases of the cycle by characterization of peak frequency, period, and amplitude. A specific secretory concomitance was assessed between LH and FSH in the follicular but not the luteal phase, and a tight concomitance between LH and PRL was demonstrated during both phases. CONCLUSIONS: These results are supportive of significant pulsatile secretions of the three hormones during the menstrual cycle, and they are demonstrative of a definite copulsatility of these hormones, suggestive of common regulatory factors in the complex temporal patterns of gonadotropin and PRL secretions along the cycle.

Secretion of hypothalamic dopamine into pituitary stalk blood of aged female rats.

Dopamine secreted into the pituitary stalk blood of old constant estrous rats (20-24 months of age) was significantly less than that of young estrous rats (3-4 months of age). Reduced concentrations of dopamine were also observed in the median eminence and in the neurointermediate lobe of the pituitary gland of old female rats compared to those of young female rats. The low rate of secretion of dopamine into pituitary stalk blood of old female rats was associated with high secretion of prolactin into arterial blood. The impaired hypothalamic secretion of dopamine observed in old rats was not affected by increased availability of L-tyrosine. However, when L-DOPA was given to old rats, very high concentrations of dopamine were measured in pituitary stalk blood, whereas the concentrations of dopamine in the arterial blood were very low. On the basis of these data, it is concluded that the neurosecretory activity of the dopaminergic neurons of the hypothalamus is impaired in old constant estrous rats. This impaired activity can be overcome by increasing the availability of L-DOPA but not L-tyrosine.

[Treatment of resistant depression with the citalopram-lithium combination. Methodology of a double-blind multicenter study and preliminary results]. / Traitement de la dépression résistante par l'association citalopram-lithium. Méthodologie d'une étude multicentrique en double aveugle et résultats préliminaires.

Citalopram, a new bicyclic antidepressant, is the most selective serotonin reuptake inhibitor. In a number of double-blind controlled studies, citalopram was compared to placebo and to known tricyclic antidepressants. These studies have shown their efficacy and good safety. The inefficacy of a psychotropic treatment in at least 20% of depressives has led a number of authors to propose original drug combinations and associations, like antidepressant/lithium (Li), antidepressant/sleep deprivation (agrypnia), antidepressant/ECT, or antidepressant/LT3. The aim of this investigation is to evaluate the clinical effectiveness and safety of a combined citalopram/lithium treatment in therapy-resistant patients, taking account of serotonergic functions, as tested by the fenfluramine/prolactin test, and of drug pharmacokinetics and pharmacogenetics of metabolism. DESIGN OF THE STUDY: A washout period of 3 days before initiating the treatment is included. After an open treatment phase of 28 days (D) with citalopram (20 mg D1-D3; 40 mg D4-D14; 40 or 60 mg D15-D28; concomitant medication allowed: chloral, chlorazepate), the nonresponding patients [less than 50% improvement in the total score on the 21 item-Hamilton Depression Rating Scale (HDRS)] are selected and treated with or without Li (randomized in double-blind conditions: citalopram/Li or citalopram/placebo) during the treatment (D29-D35). Thereafter, all patients included in the double-blind phase subsequently receive an open treatment with citalopram/Li for 7 days (D36-D42). The hypothesis of a relationship between serotoninergic functions in patients using the fenfluramine/prolactin test (D1) and the clinical response to citalopram (and Li) is assessed. Moreover, it is evaluated whether the pharmacogenetic status of the patients, as determined by the mephenytoin/dextromethorphan test (D0-D28), is related to the metabolism of fenfluramine and citalopram, and also to the clinical response. CLINICAL ASSESSMENT: Patients with a diagnosis of major depressive disorders according to DSM III are submitted to a clinical assessment of D1, D7, D14, D28, D35, D42: HDRS, CGI (clinical global impression), VAS (visual analog scales for self-rating of depression), HDRS (Hamilton depression rating scale, 21 items), UKU (side effects scale), and to clinical laboratory examens, as well as ECG, control of weight, pulse, blood pressure at D1, D28, D35. Fenfluramine/prolactin test: A butterfly needle is inserted in a forearm vein at 7 h 45 and is kept patent with liquemine. Samples for plasma prolactin, and d- and l-fenfluramine determinations are drawn at 8 h 15 (base line). Patients are given 60 mg fenfluramine (as a racemate) at 8 h 30. Kinetic points are determined at 9 h 30, 10 h 30, 11 h 30, 12 h 30, 13 h 30. Plasma levels of d- and l-fenfluramine are determined by gas chromatography and prolactin by IRNA. Mephenytoin/dextromethorphan test: Patients empty their bladders before the test; they are then given 25 mg dextropethorphan and 100 mg mephenytoin (as a racemate) at 8 h 00. They collect all urines during the following 8 hours. The metabolic ratio is determined by gas chromatography (metabolic ratio dextromethorphan/dextrorphan greater than 0.3 = PM (poor metabolizer); mephenytoin/4-OH-mephenytoin greater than 5.6, or mephenytoin S/R greater than 0.8 = PM). Citalopram plasma levels: Plasma levels of citalopram, desmethylcitalopram and didesmethylcitalopram are determined by gas chromatography--mass spectrometry. RESULTS OF THE PILOT STUDY. The investigation has been preceded by a pilot study including 14 patients, using the abovementioned protocol, except that all nonresponders were medicated with citalopram/Li on D28 to D42. The mean total score (n = 14) on the 21 item Hamilton scale was significantly reduced after the treatment, ie from 26.93 +/- 5.80 on D1 to 8.57 +/- 6.90 on D35 (p less than 0.001). A similar patCitalopram, a new bicyclic antidepressant, is the most selective serotonin reu

[A new in vitro model allows use of the same hypothalamus for morphological and functional studies]. / Un nouveau modèle in vitro permet d'employer le même hypothalamus pour des investigations morphologiques et functionnelles.

A model for combined morphological and functional investigations on the isolated rat mediobasal hypothalamus has been developed. Under these conditions of incubation, the hypothalamic tissue is well preserved, on the basis of photonic and electronic microscopic examinations. This model has been used to study the LHRH system in the rat. LHRH release has been measured in the incubation medium under basal conditions and after KCl-induced depolarisation; the, LHRH has been localized by immunohistochemistry on the hypothalamic fragment.