Long-term follow-up of cystic thyroid nodules treated with percutaneous ethanol injection (PEI) using two different approaches.

BACKGROUND AND AIM: Cystic thyroid nodules (CNs), although generally benign, can cause compressive or aesthetic problems. Percutaneous ethanol injection (PEI) can represent an alternative to surgery. The present retrospective study evaluates: (i) the long-term outcome of CNs after PEI; (ii) the differences between two different PEI protocols; (iii) the CNs response according to the liquid component. MATERIALS AND METHODS: The study comprises 358 nodules post-PEI followed for at least 2 years. PEI was performed according to two different treatment protocols with a single (Foggia) or double (Turin) alcohol injection. CNs were divided according to their composition: cystic (CYS) >90%, mainly cystic (M-CYS) 75-90%, mixed (MIX) 50-75%, solid-mixed (S-MIX) 35-50%. The volume reduction rate (VRR) was defined as nodule volume (mL) after PEI/nodule volume (mL) before PEI x 100. RESULTS: The 1-year VRR was significantly higher than that at 6 months (89.5% vs 72.9%, P = 0.0005), no differences were observed after 1 year. A significant difference between Turin and Foggia was observed only in VRR at early visit (79% vs 86%, respectively, P = 0.002) and recurrence rate (14% vs 24%, respectively, P = 0.001). Minor side-effects were infrequent. In 192 nodules with a 10-year follow-up CYS showed higher VRR than MIX and S-MIX nodules (P < 0.001). CONCLUSION: Our study reported that the long-term outcome of CNs treated with PEI is excellent regardless of the PEI technique utilized; the larger the cystic amount, the higher the VRR. Based on present results, PEI can be considered as the first-line choice for treating thyroid CNs.

Primary hyperaldosteronism is associated with derangement in the regulation of the hypothalamus-pituitary-adrenal axis in humans.

Hippocampal mineralocorticoid receptors (MR) play a major role in the control of hypothalamus- pituitary-adrenal (HPA) axis. The functional profile of HPA axis and the impact of MR blockade under chronic exposure to mineralocorticoid excess are unknown. To clarify this issue, ACT H, cortisol, and aldosterone secretions were studied in 6 patients with primary hyperaldosteronism (HA) and 8 controls (NS) during placebo, placebo+human CR H (hCR H) (2 microg/kg iv bolus at 22:00 h), potassium canrenoate (CAN, 200 mg iv bolus at 20:00 h followed by 200 mg infused over 4 h) or CAN+hCR H. During placebo, both aldosterone and ACT H levels were higher (p<0.01) in HA than in NS, while cortisol levels were not significantly different. Both HA and NS showed significant ACT H and cortisol responses to hCR H (p<0.004), although the hormonal responses in HA were higher (p<0.02) than in NS. CAN infusion did not modify aldosterone levels in both HA and NS. Under CAN infusion, ACT H showed progressive rise in NS (p<0.05) but not in HA, while cortisol levels showed a significant (p<0.05) but less marked and delayed increase in HA compared to NS. CAN enhanced hCRH-induced ACTH and cortisol responses in NS (p<0.05), but not in HA. In conclusion, in humans primary hyperaldosteronism is associated with deranged function of the HPA axis. In fact, hyperaldosteronemic patients show basal and hCR H-stimulated HPA hyperactivity that is, at least partially, refractory to further stimulation by mineralocorticoid blockade with canrenoate. Whether this hormonal alteration can influence the clinical feature of hypertensive patients with primary hyperaldosteronism needs to be clarified.

Hypovitaminosis D in internal medicine inpatients.

Some studies have suggested that hypovitaminosis D may be a consequence of protein-calorie malnutrition. This study assessed both the relationship between vitamin D status, malnutrition, calcium and phosphorus metabolism indices and the importance attached by internists to these alterations. There were 239 patients admitted to an internal medicine division who underwent examinations to assess nutritional state, liver and renal function, and bone metabolism. At the end of the study, the clinical data included in the discharge letter, the treatment prescribed, and the diagnosis assigned to patients on their hospital discharge form were collected. Hypovitaminosis D was found in 72% and hypoalbuminemia in 34.3% of patients. Subjects with hypovitaminosis were generally older and had lower albumin levels than those with mild or no hypovitaminosis. 25-Hydroxyvitamin D was inversely related with parathyroid hormone and directly related with albumin. Alterations of calcium and phosphorus metabolism were present in 55.6% and recorded by the division's physicians for only 13.53% of patients, of whom 72.37% were not specifically treated. There is a direct correlation between 25-hydroxyvitamin D and albumin levels. The high incidence and the metabolic consequence of hypovitaminosis D and of protein-calorie malnutrition is significantly underestimated and undertreated by physicians.

Insulin sensitivity is impaired in patients with migraine.

Several studies have shown the presence of a comorbidity between migraine and vascular diseases, like hypertension and stroke. The mechanisms of this comorbidity are unknown. Impaired insulin sensitivity has recently emerged as a risk factor for hypertension and stroke. We evaluated insulin sensitivity in 30 young, nonobese, nondiabetic, normotensive migraine patients and in 15 healthy controls. During the OGTT, glucose plasma concentrations were significantly higher in migraineurs than in controls. Insulin sensitivity, as measured by ISI-stumvoll and OGIS-180 indexes, was significantly altered in migraine. Our data show that insulin sensitivity is impaired in migraine and suggest a role for insulin resistance in the comorbidity between migraine and vascular diseases.

Abnormal 5-HT1D receptor function in cluster headache: a neuroendocrine study with sumatriptan.

The purpose of this study was to assess the sensitivity of 5-HT(1D) receptors in patients with episodic cluster headache using sumatriptan as a pharmacological probe. The drug, a selective 5-HT(1B/1D) agonist, stimulates the secretion of growth hormone and inhibits the release of prolactin, adrenocorticotropic hormone (ACTH) and cortisol. These effects may be used to explore the function of serotonergic systems in vivo. We administered subcutaneous sumatriptan and placebo to 20 patients with cluster headache (10 in the active phase and 10 in the remission period) and to 12 controls. The sumatriptan-induced increase of growth hormone concentrations was significantly (P < 0.05) blunted in patients with active cluster headache. Prolactin and ACTH responses to the drug were significantly (P < 0.05) reduced in patients with cluster headache, both in the active and in the remission period. Our results suggest that cerebral serotonergic functions mediated by 5-HT(1D) receptors are altered in patients with episodic cluster headache.

Decreased sensitivity of 5-HT1D receptors in chronic tension-type headache.

OBJECTIVE: To assess the sensitivity of 5-HT1D receptors in chronic tension-type headache using sumatriptan as a pharmacological probe. BACKGROUND: Previous studies have suggested involvement of serotonergic systems in chronic tension-type headache (CTTH), but relevant experimental data are limited. Sumatriptan, a 5-HT1B/1D receptor agonist, stimulates the release of growth hormone (GH) and inhibits the release of ACTH, cortisol, and prolactin. These effects may be used to explore the function of serotonergic systems in vivo. METHODS: We measured GH, ACTH, cortisol and prolactin (PRL) plasma concentrations in 15 patients with chronic tension-type headache and in 18 healthy controls after subcutaneous administration of sumatriptan (6 mg) or placebo. RESULTS: Placebo administration had no effect on hormone concentrations. GH and PRL secretion after sumatriptan administration was significantly (P<0.01 and <0.05) altered in CTTH patients in comparison with controls. CONCLUSION: Our results suggest that cerebral serotonergic functions mediated by 5-HT1D receptors are altered in CTTH.

Effects of high doses of corticosteroids on bone metabolism.

The effects of a chronic treatment with corticosteroids on bone are well known, but few data are available regarding the acute effect of these drugs on bone turnover. This study was aimed at evaluating the effects of high doses of corticosteroids administered for a short period on bone metabolism. We assessed 23 subjects (15 women and 8 men) suffering from multiple sclerosis and treated with methylprednisolone (1 g i.v. for 10 days) followed by oral prednisone for 9 days; patients affected by diseases involving bone or treated during the previous 6 months with drugs influencing bone metabolism were excluded. We observed a significant decrease of ALP and bone glia protein (BGP), in these subjects, and a significant sudden increase of urinary calcium/creatinine and urinary cross-laps after 3 days of treatment. All of these parameters, except urinary calcium/creatinine, returned to basal levels after 30 days from the beginning of treatment (11 days after the interruption of corticosteroids administration). Serum phosphorus showed a significant decrease after 3 days of treatment, but returned to basal levels after 10 days. These data suggest that high doses of corticosteroids administered for a short period are able to induce an increase of bone resorption and a decrease of bone formation; moreover, bone turnover returns to basal levels when the treatment is stopped.

Failure of angiotensin II and insulin to stimulate transforming growth factor-beta1. Release from cultured bovine retinal pericytes.

BACKGROUND: Activation of the renin-angiotensin system (RAS) may induce cardiovascular and renal fibrosis in hypertension and diabetes. This fibrogenic effect is mainly mediated by Transforming Growth Factor-B1 (TGF-B1), a multifunctional citokyne released by endothelial, vascular smooth muscle and renal mesangial cells, that is able to increase extracellular matrix deposition. Retinal capillary pericytes have functions similar to those of mesangial cells, including ability to synthesize and release TGF-B1 and produce extracellular matrix. An intraocular RAS was described in the human eye and may produce effects similar to those observed in the heart and kidney, which could be mediated by TGF-B1. In particular, TGF-B1 might be involved in thickening of the capillary basement membrane in diabetic microangiopathy. We therefore aimed at evaluating the possible effects of Angiotensin-II on TGF-B1 secretion by cultured retinal pericytes (BRP). METHODS: BRP cultures were incubated with Angiotensin-II or insulin (known to play a permissive effect on TGF-B1 release from mesangial cells) or Angiotensin-II + insulin at final concentrations of 10-10, 10-8, 10-6, 10-4 mol/L. RESULTS: Baseline TGF-B1 concentrations in the supernatants of pericyte cultures were 6 139 +/- 1 919 pg/mL/106 cells; no changes of TGF-B1 concentrations resulted from adding increasing amounts of Ang II, insulin or both. CONCLUSIONS: Though confirming that cultured bovine retinal pericytes spontaneously release TGF-B1, Angiotensin-II did not produce any stimulatory effects of in our experimental system

Neuroendocrine effects of subcutaneous sumatriptan in patients with migraine.

We evaluated the sensitivity of 5-HT1D receptors in patients with migraine using sumatriptan as a pharmacological probe. The drug inhibits the release of ACTH, cortisol and prolactin and this effect may be used to explore the function of serotoninergic systems in vivo. We administered sumatriptan (6 mg sc) and placebo to 15 migraineurs, during the headache-free period, and to 10 healthy controls. Blood samples were collected -15, 0, 15, 30, 45, 60 and 90 min after injections. Sumatriptan induced a significant (p<0.01) decrease of ACTH, cortisol and prolactin concentrations both in patients with migraine and in controls. The neuroendocrine response was not significantly different in the two groups. Our results suggest that 5-HT1D receptor sensitivity is not altered in migraine.

Effects of subcutaneous sumatriptan on plasma growth hormone concentrations in migraine patients.

The purpose of this study was to assess the sensitivity of 5-HT1D receptors in migraine using sumatriptan as a pharmacological probe. The drug stimulates the release of growth hormone (GH) and this effect may be used to explore the function of cerebral serotonergic systems in vivo. We administered sumatriptan and placebo to 15 migraineurs and to 10 controls. Blood samples were collected -15, 0, 15, 30, 45, 60 and 90 min after injection. Placebo had no effect on hormone concentrations. Sumatriptan induced a significant (P<0.01) increase in GH concentrations both in migraine patients and healthy controls. The GH increase was not significantly different in the two groups. Our results suggest that cerebral serotonergic functions mediated by 5-HT1D receptors are not altered in migraine. Sumatriptan overuse could lead to adverse effects mediated by its neuroendocrine activity.

Evidence for a positive correlation between serum cortisol levels and IL-1beta production by peripheral mononuclear cells in anorexia nervosa.

A hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis has been reported in anorexia nervosa (AN), together with some immunological abnormalities, involving citokine - and particularly Tumor Necrosis-Factor-alpha (TNF-alpha) - production by polymorphonuclear cells. The ability of pro-inflammatory cytokines to activate the HPA axis is well known; however, there are no data demonstrating an interdependence between immunological and endocrine response in AN. To investigate the presence of a correlation between immune response and pituitary-adrenal function, plasma ACTH and serum cortisol concentrations were measured in 13 AN patients and in the same number of controls. TNF-alpha and interleukin (IL)-1beta production by ex-vivo unstimulated and LPS-stimulated peripheral mononuclear cells was also assessed. Circulating cortisol concentrations were higher (p<0.01) in AN (156.7 +/- 45.1 microg/l, mean +/- SD) than in controls (105.9 +/- 25.7 microg/l). Unstimulated IL-1beta release in supernatants of mononuclear cell cultures was slightly but not significantly higher in AN than in controls, while TNF-alpha release was similar in the two groups. A positive correlation was found between IL-1beta concentrations in unstimulated culture supranatants and serum cortisol levels in AN (r=0.782, p=0.002), while in normal subjects there was a trend toward a negative correlation; a slight positive correlation, while not significant, between IL-1beta and plasma ACTH, as well as between TNF-alpha and serum cortisol was also found in AN. These data suggest that the normal relationship between pro-inflammatory cytokines release, particularly IL-1beta, and cortisol secretion is deranged in AN.

Diagnosis of glucocorticoid-remediable aldosteronism in primary aldosteronism: aldosterone response to dexamethasone and long polymerase chain reaction for chimeric gene.

Aldosterone suppression by dexamethasone, and high 18-hydroxycortisol and 18-oxocortisol levels are used to differentiate glucocorticoid-remediable aldosteronism (GRA) from other forms of primary aldosteronism. These methods are time consuming, expensive, and impractical for large studies. Moreover, diagnosis of GRA requires a confirmatory genetic test. We evaluated 117 patients with primary aldosteronism referred to our centers by the use of a long PCR technique to reveal the chimeric gene of GRA. In 60 of 117 patients, the response of aldosterone to dexamethasone (2 mg/day for 4 days) was also assessed. None of our patients, including 2 pairs of siblings, was positive for the chimeric gene. The results of long PCR were confirmed by Southern blotting. Despite a negative genetic test, 6 patients (1 with aldosterone-producing adenoma and 5 with idiopathic hyperaldosteronism) had plasma aldosterone suppressed by dexamethasone (i.e. < or = 2 ng/dL). Of 117 patients, 43 were identified as having aldosterone-producing adenoma and 74 as having idiopathic hyperaldosteronism. In our experience, the long PCR technique is a reliable and simple test to at least exclude GRA in patients with primary aldosteronism. A short term dexamethasone suppression test of aldosterone can be misleading in identifying GRA. The prevalence of GRA in primary aldosteronism remains to be established.

[Primary hyperaldosteronism. Update on a topic of physiopathology and clinical features]. / L'iperaldosteronismo primitivo. Attualità in tema di fisiopatologia e clinica.

The authors examine the various forms of primary hyperaldosteronism, outlining the most recent acquisitions in terms of etiopathogenesis and physiopathology. While Conn's original description of primary hyperaldosteronism is a syndrome based on corticoadrenal aldosteronesecreting adenoma, it was later seen that this condition could recognise other anatomic substrates, such as carcinoma and in particular bilateral corticoadrenal hyperplasia. A peculiar form of the latter can be suppressed with glucocorticoids sustained by an anomalous recombination of aldosterone-synthase and 11-beta-hydroxylase. The main focus in this paper is on clinical management, in particular the current diagnostic criteria which show that primary hyperaldosteronism affects a higher percentage of the hypertense population that was estimated in the past. Above all, the significance of the aldosterone/PRA (ARR) ratio in screening for this condition is discussed, above all in normokalemic forms, together with the role of molecular biology in identifying glucocorticoid-suppressible forms. Lastly, the principles of medical and surgical management are outlined, emphasising the role of laparoscopic surgery.

Evidence for an interaction between alpha-MSH and opioids in the regulation of gonadotropin secretion in man.

Gonadotropin secretion is inhibited by the endogenous opioids and stimulated by their antagonist naloxone. LH secretion is stimulated by alpha-MSH, a tridecapeptide derived from the post-translational processing of POMC. The possibility that alpha-MSH interacts with the opioids, as suggested by the experimental evidence, was investigated in 7 normal males aged 24-29 through the performance of seven tests: naloxone (0.8 mg i.v. bolus, followed by infusion of 1.6 mg/h for 120'); alpha-MSH (2.5 mg i.v. bolus); naloxone + alpha-MSH (2.5 mg i.v. 15' after commencement of the naloxone infusion); naloxone + GnRH (100 micrograms i.v. 15' after commencement of the naloxone infusion); alpha-MSH + GnRH (respectively 2.5 mg and 100 micrograms at time 0), GnRH alone (100 micrograms at time 0), placebo (150 nmol/l NaCl solution). The LH AUCs during both naloxone (30.3 +/- 2.7 mIU/ml.min-1) and alpha-MSH test (32.9 +/- 4.6 mIU/ml.min-1) were significantly greater (p < 0.005) than that observed during placebo (16.9 +/- 3.6 mIU/ml.min-1). The LH AUC during alpha-MSH + naloxone (37.6 +/- 2.6 mIU/ml.min-1) was not significantly different from that recorded during their separate administration. GnRH injected alone, during the naloxone infusion and with alpha-MSH produced similar increases in LH, that were significantly higher than that observed during the other tests (AUCs: GnRH 89.4 +/- 10.6, GnRH + naloxone 100.5 +/- 9.1, GnRH + alpha-MSH 94.6 +/- 7.9 mIU/ml.min-1, p < 0.001). Significant increase in FSH (p < 0.001) was only observed during GnRH, GnRH + naloxone and GnRH + aMSH tests (AUCs: placebo 13.3 +/- 1.7; naloxone 14.7 +/- 2.5; alpha-MSH 15.5 +/- 2.3; alpha-MSH + naloxone 16.9 +/- 1.9; GnRH 19.1 +/- 1.1; GnRH + alpha-MSH 20.7 +/- 1.3; GnRH + naloxone 21.2 +/- 1.8 mIU/ml.min-1). These results are in line with the possibility of an interaction between alpha-MSH and the opioids in the regulation of gonadotropin secretion, perhaps with opposing effects on a final common pathway.

Hypertension and oedema caused by cortexone hyperproduction and cured by monolateral adrenalectomy. Case report.

Excess 11-deoxycorticosterone (DOC) production, mostly due to an enzyme defect 11-beta-hydroxylase, is a rare cause of secondary hypertension. Even rarer are those forms due to an adrenal adenoma or to a bilateral hyperplasia. In this paper we report the case of 23-year-old woman with excess DOC production, presenting with arterial hypertension and oedema, whom we first observed in 1961. Complete clinical remission, persisting more than 30 years later, was obtained by monolateral adrenalectomy. The literature reports of DOC-induced hypertension due to adrenal adenoma or hyperplasia are reviewed and the possible pathogenetic mechanisms are discussed.

The inhibitory effect of glucose on growth hormone secretion is lost in obesity but not in hypertension.

In obesity there is a clear reduction of both spontaneous and stimulated GH secretion. Furthermore, in obese patients the somatotrope responsiveness to provocative stimulation is selectively refractory to the inhibitory effect of glucose load. It has been hypothesized that hyperinsulinism of obese patients could play a role in the pathogenesis of these alterations. Aim of the present study was to verify the GH response to GHRH and the ability of glucose load to inhibit it in patients with essential hypertension in whom hyperinsulinism and insulin resistance are frequently present. To this goal, 7 patients with essential hypertension (HP, age, mean +/- SE: 29.6 +/- 2.4 yr, 3 females and 4 males, BMI: 21.7 +/- 1.2 kg/m2), 7 obese (OB, 4 females and 3 males, 31.9 +/- 4.1 yr, 35.6 +/- 2.0 kg/m2) and 7 normal subjects (NS, 4 females and 3 males, 28.3 +/- 3.9 yr, 21.0 +/- 1.6 kg/m2) underwent the following tests: GHRH (1 microgram/kg i.v. at time 0) alone and preceded by oral glucose load (OGTT, 100 g po at -45 min). Basal insulin levels were similar in HP and OB (11.3 +/- 0.5 and 12.7 +/- 2.2 microU/ml, respectively); these, in turn, were higher (p < 0.005) than those in NS (6.8 +/- 0.8 microU/ml). Basal plasma glucose levels in HP were similar to those in OB and NS (80.3 +/- 3.6, 86.9 +/- 6.7 and 84.4 +/- 1.7 mg/dl, respectively). In HP and OB and NS basal GH (1.0 +/- 0.5, 1.0 +/- 0.6 and 0.3 +/- 0.1 micrograms/l, respectively) and IGF-I levels (132.6 +/- 14.8, 137.3 +/- 13.2 and 138.8 +/- 12.2 micrograms/l, respectively) were similar. In HP the GH response to GHRH (AUC: 1058.8 +/- 347.8 micrograms/l/min) was similar to that observed in NS (959.0 +/- 167.8 micrograms/l/min) and higher than that in OB (344.8 +/- 67.2 micrograms/l/min, p < 0.01). OGTT clearly blunted (p < 0.01) the GHRH-induced GH response in HP as well as in NS (401.8 +/- 104.4 and 521.6 +/- 76.6 (g/l/min, respectively) but not in OB (387.4 +/- 78.8 (g/l/min). The OGTT-induced insulin levels in HP did not differ from those of OB, both being higher (p < 0.05) than those recorded in NS. Glucose levels after OGTT were similar in the three groups. In conclusion, this study demonstrates that, like in normal subjects but differently from in obese patients the GH response to GHRH is normal in patients with essential hypertension and it is normally inhibited by oral glucose load even when these patients show high insulin levels. Thus, it is unlikely that the low somatotrope secretion and its refractoriness to inhibition by glucose load in obesity is due to hyperinsulinism.

Altered adrenocorticotropin and cortisol response to corticotropin-releasing hormone in HIV-1 infection.

Alterations of the hypothalamic-pituitary-adrenal (HPA) axis are common in HIV infection. To characterize further the site of these derangements and their possible causes, eight male drug addicts with symptomatic HIV infection (stage IV C2) underwent the following investigations: repeated baseline determinations of cortisol, adrenocorticotropin (ACTH), interleukin 1 beta (IL-1 beta), IL-6 and interferon alpha (IFN-alpha); and ovine corticotropin-releasing hormone (CRH) test (100 micrograms IV) for ACTH and cortisol determinations. Baseline cortisol levels were either normal or elevated in all patients. A significant linear correlation was found between baseline levels of cortisol and both IL-6 (r = 0.955; p < 0.001) and IL-1 beta (r = 0.863; p < 0.005), but not between cortisol and ACTH or between ACTH and circulating cytokines. Both ACTH and cortisol responses to CRH were nearly absent in six out of eight patients, and delayed in the others. The areas under the curves of both ACTH and cortisol after CRH were significantly lower in HIV patients than in a group of eight healthy control subjects (p = 0.0157 for ACTH and p = 0.046 for cortisol). Out data suggest the possibility of an inappropriate stimulation of the HPA axis in symptomatic HIV infection by HIV-induced release of cytokines, with a blunted pituitary and adrenal response to CRH.

Treatment of Cushing's disease by interstitial pituitary irradiation: short- and long-term follow-up.

Trans-sphenoidal intrasellar implantation of radioactive rods was employed to treat Cushing's disease in our Institution between 1958 and 1981. The patients were followed at regular intervals after the procedure. The aim of this work is to assess retrospectively the results, comparing the short- (1 year) and long-term (average 21.8 years) effects of this treatment. Seventy-six patients received pituitary implantation of 90Y- and one of 198Au-labelled rods, delivering a dose of 100-150,000 rad. Complete remission was obtained in a few weeks to months in 57/76 patients (5 of whom required a second implantation); 2 patients died of meningoencephalitis and 3 of cardiovascular complications associated with hypercortisolism 1 to 2 months after surgery. In 12 patients bilateral adrenalectomy or external pituitary irradiation were required to achieve remission; one of them developed Nelson's syndrome 15 years after implantation. Two were lost at follow-up. Long-term follow-up was possible in 41 patients of the initial series. Of these, 40 were cured of the disease, with hypoadrenalism developing in 25, while recurrence was observed only in the patient treated with 198Au. The incidence of hypothyroidism was 50%, and that of hypogonadism 54%. Permanent diabetes insipidus developed in 1 subject. GH deficiency resulting in retarded growth was found in the youngest patient, who had been operated at the age of 14. In conclusion, interstitial irradiation of pituitary adenomas was a safe and effective procedure for the treatment of Cushing's disease.

Alpha-melanocyte-stimulating hormone antagonizes the inhibitory effect of corticotropin-releasing hormone on luteinizing hormone secretion during the luteal phase in normal women.

CRH inhibits the secretion of gonadotropins by activating endogenous opioids, whereas alpha MSH, which displays various behavioral and neuroendocrine effects contrary to those of the opioids, stimulates their release. To evaluate the possible interaction of CRH and alpha MSH, eight women in the luteal phase underwent the following tests: 1) ovine CRH infused at 100 micrograms/h for 3 h, 2) alpha MSH (2.5 mg as an iv bolus 60 min after the start of saline infusion), 3) CRH plus alpha MSH (injected 60 min after the start of CRH infusion), and 4) placebo. LH, FSH, PRL, ACTH, and cortisol were determined every 15 min for 180 min. CRH significantly (P < 0.001) reduced serum LH. alpha MSH alone significantly (P < 0.001) increased LH to a peak within 15-30 min (baseline, 3.3 +/- 0.7 mIU/mL; maximum increase, 3.5 +/- 0.9 mIU/mL) and induced an even greater rise when injected during the CRH infusion (baseline, 2.8 +/- 03 mIU/mL; maximum increase 7.5 +/- 1.6 mIU/mL; P < 0.05 vs. alpha MSH alone). FSH was always unaffected. ACTH and cortisol increased (P < 0.001) during the CRH infusion and fell significantly (P < 0.001) during the placebo infusion. alpha MSH had no effect on these changes. PRL fell during the placebo infusion (P < 0.001). No changes were induced by CRH or alpha MSH. In conclusion, alpha MSH antagonizes CRH inhibition of LH secretion. This finding lends support to the view that differential posttranslational processing of POMC contributes to the regulation of LH secretion. Further investigation is needed to clarify the mechanism of the antagonism between alpha MSH and CRH.

Enhanced adrenocorticotrophic hormone and cortisol responses to corticotrophin-releasing hormone in central idiopathic diabetes insipidus.

It is well known that arginine vasopressin (AVP) exerts a stimulatory effect on adrenocorticotrophic hormone (ACTH) secretion. Moreover, there is consistent evidence that the hypothalamic AVP-secreting neurons are involved in the neuroregulation of ACTH secretion. With the aim to throw further light on the interaction between AVP and corticotrophin-releasing hormone (CRH) in the neuroregulation of ACTH secretion, in this study we compared the ACTH and cortisol responses to human CRH (100 micrograms iv as a bolus) in 18 normal subjects (15 females and three males, age 22-35 years) and seven patients with central isolated diabetes insipidus (six females and one male, age 16-40 years). Two patients were newly diagnosed and five had discontinued substitution therapy with desamino-D-AVP 24 h before testing. All had free access to water before and during the test period. The ACTH and cortisol responses to CRH were higher in subjects with diabetes insipidus than in controls, either when evaluated as peak values (ACTH, mean +/- SEM: 17.0 +/- 1.2 vs 7.7 +/- 0.7 pmol/l, p = 0.0003; cortisol: 611.3 +/- 59.4 vs 450.7 +/- 21.2 nmol/l, p = 0.01) or area under curve values (ACTH: 672.5 +/- 75.7 vs 364.0 +/- 33.6 pmol.l-1 x h-1, p = 0.002; cortisol: 29158.0 +/- 2937.0 vs 23236.7 +/- 1052.1 nmol.l-1 x h-1, p = 0.03). These results show that patients with diabetes insipidus have an exaggerated pituitary-adrenal response to CRH. This may be due to the fact that in diabetes insipidus AVP secretion from parvocellular neurons of the paraventricular nucleus in the hypophysial portal system is not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)