Prolactin-lowering effect of luteinizing hormone-releasing hormone agonist administration in prolactinoma patients.

We studied the effect of LHRH agonist administration on serum PRL levels in five women with microprolactinomas and two women and a man with intrasellar macroprolactinomas. Each patient received either D-Trp6-LHRH or buserelin for 90 days. Serum PRL levels decreased significantly in the patients with microprolactinomas by 65%, from 156 +/- 93 (+/- SD) to 54 +/- 49 micrograms/L on day 90 (P = 0.011), but it did not decrease in the macroprolactinoma patients. Mean serum LH and FSH decreased by 43% and 62.5%, respectively, in all eight patients. There was no statistically significant correlation between the serum PRL and LH or FSH levels in the microprolactinoma patients. We conclude that LHRH agonists can counteract the hyperprolactinemia produced by microprolactinomas and that the effect probably is not exerted by an action on the gonadotrophs.

D-Trp6-luteinizing hormone-releasing hormone inhibits sulpiride-induced hyperprolactinemia in normal men.

The effect of a potent agonistic analog of LHRH, D-Trp6-LHRH, on hyperprolactinemia induced by sulpiride was studied in normal men. Six men received sulpiride (100 mg, twice daily, orally) for 44 days. D-Trp6-LHRH was given sc during the last 2 weeks of sulpiride administration; the dose was 500 micrograms on the first day and 100 micrograms daily for the subsequent 14 days. All men had high serum PRL levels before D-Trp6-LHRH administration (mean +/- SEM, 56 +/- 9 ng/mL), which decreased significantly after the first dose of the analog (45 +/- 5 ng/mL; P = 0.031) and also after 15 days of analog administration (41 +/- 6 ng/mL; P = 0.016). These data demonstrate that administration of LHRH agonist can inhibit the hyperprolactinemic effect of sulpiride, suggesting a direct action of the analog on the pituitary gland to modulate PRL secretion.

Effects of different proportions of carbohydrates, polysaccharides/monosaccharides, and different fibers on the metabolic control in diabetic rats.

Recent findings have suggested that diets with a high level of carbohydrates may impair the metabolic control of diabetes mellitus in humans. Moreover, other investigations have indicated that if the simple sugar content is increased in order to attain a proportion of polysaccharides/monosaccharides equal to 1, then neither the blood glucose nor the lipidic response show any change. We have studied the effect of increasing carbohydrates in the diet (59% v 82%), while maintaining cereal fiber levels constant (30%) and replacing cereal fiber in high carbohydrate diets by guar gum (30%) and lentil-derived leguminous fiber (30%) on the metabolic control of streptozotocin-induced diabetic rats. A study with different diets was performed for 3 weeks. An increase of carbohydrates in the diet produces an increase in the HbA1 concentration (1.9% v 3.9%, P less than 0.01) and in serum triglyceride levels (98.75 +/- 22.09 mg/dL v 144.50 +/- 3.52 mg/dL, P less than 0.05). Total cholesterol and HDL-cholesterol levels remained unchanged. The increase does not occur if the cereal fiber is replaced by lentil-derived leguminous fiber. In a second experiment, we substituted 50% of the complex carbohydrates in diets with 80% carbohydrates by glucose. Blood glucose, triglycerides, and HbA1 levels rose significantly in the four groups of rats that received diets containing 50% carbohydrates in glucose form. In addition, a test meal was carried out on day 19, consisting of 2.5 g of food/kg of wt. The maximum increase in blood glucose and the area below the glucose curve response was also significantly higher in the four groups of rats who received glucose in their diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of [D-Trp6]LHRH infusion on prolactin secretion by perifused rat pituitary cells.

The effect of a superactive agonistic analog of luteinizing hormone-releasing hormone (LHRH), [D-Trp6]LHRH on prolactin (PRL) secretion by perifused rat pituitary cells was investigated. Constant infusion of [D-Trp6]LHRH (0.5 ng/min) for 2-3 h elicited a significant decrease in PRL secretion by these cells. This decrease in PRL release started ca. 30 min after the beginning of the infusion with the LHRH analog and lasted up to 1.5-2 h. [D-Trp6]LHRH significantly stimulated luteinizing hormone (LH) secretion during the first 30 min of peptide infusion; thereafter, LH levels began to return to control values. In animals pretreated in vivo with 50 micrograms of [D-Trp6]LHRH (s.c.) 1 h before sacrifice, PRL secretion by the rat pituitary cell perifusion system was significantly lower than vehicle-injected controls throughout the entire [D-Trp6]LHRH infusion period. On the other hand, thyrotropin-releasing hormone (TRH)-stimulated PRL secretion was slightly, but significantly imparied by [D-Trp6]LHRH infusion, while dopamine (DA) inhibition of PRL release was unaffected by this same treatment. These results reinforce previous observations of a modulatory effect of [D-Trp6]LHRH, probably mediated by pituitary gonadotrophs, on PRL secretion by the anterior pituitary. In addition, our findings suggest that basal PRL secretion by the lactotroph may be dependent on a normal function of the gonadotroph. The collected data from this and previous reports support the existence of a functional link between gonadotrophs and lactotrophs in the rat pituitary gland.

Behaviour modification in obese subjects with type 2 diabetes mellitus.

We have followed prospectively, 46 obese, type 2 diabetic patients for a 55-week period, in order to evaluate the efficiency of an educational programme based on behaviour modification to enhance weight loss and changes of other cardiovascular risk factors. No patient received pharmacological treatment during the study. At the end of the follow-up the patients obtained an average weight loss of 9.250 kg (range: 0.500-17.500 kg); the BMI was reduced from 34.2 +/- 0.8 kg/m2 to 30.6 +/- 1.1 kg/m2 (P less than 0.01); fasting serum glucose descended from 7.9 +/- 0.4 to 6.1 +/- 0.5 mM (P less than 0.05); SBP (systolic blood pressure) decreased from 145.7 +/- 3 to 126.4 +/- 5.1 mmHg (P less than 0.01); DBP (diastolic blood pressure) decreased from 83.5 +/- 2.5 to 65 +/- 2.6 mmHg (P less than 0.01); triglyceride levels were lowered from 164.5 +/- 12 to 109.7 +/- 10 mg/dl (P less than 0.01); HDL-cholesterol levels increased from 1.27 +/- 0.05 to 1.53 +/- 0.12 mM (P less than 0.01). Serum glucose 2 h after a 75 g glucose oral load decreased from 14.9 +/- 0.6 to 12.7 +/- 0.9 mM (P less than 0.05) on week 35 of follow-up. Twelve patients no longer presented a diabetic curve (8 normal oral glucose tolerance test (OGTT) curves, and 4 impaired glucose tolerance (IGT) curves). No significant changes in the parameters studied were obtained in the group of patients on conventional treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of peripheral arterial reconstruction in diabetic and non-diabetic patients: a prospective clinic-based study.

UNLABELLED: To assess the efficacy and safety of lower extremity arterial reconstruction in diabetic and non-diabetic subjects during a 3-year period. A prospective clinic-based study between 1994-1999 in Area 7, Madrid, with a population of 569307 and an estimated diabetic population of 37932 (15505 men and 22427 women). The level of arterial reconstruction and associated risk factors were ascertained. RESULTS: A total of 588 peripheral revascularization surgical procedures were performed in 481 patients. The diabetic patients (n=174, 36.2%) underwent 222 surgical procedures (including 48 follow-on operations, 21.6%), and 307 non-diabetic subjects underwent 366 surgical procedures (59 follow-on operations, 16.1%). The numbers of surgical procedures per 100000 people at risk and year were 18.8 and 1.8 for non-diabetic men and women, respectively, and 145.1 and 29.0 for men and women with diabetes mellitus (7.7- and 16.2-fold, respectively). Age at reconstruction surgery was 2 and 5 years earlier in non-diabetic than in diabetic men and women, respectively. Diabetic patients had a higher neuropathy score (P<0.05) and were less frequently smokers (P<0.05) than non-diabetic subjects. Diabetic subjects more frequently had distal reconstruction while proximal arterial reconstruction was more often performed in non-diabetic subjects. Between 64.6 and 80.4% of people with diabetes and 82.3 and 88.9% of non-diabetic subjects had no complications during their in-hospital stay. Distal amputation simultaneous to arterial reconstruction was the most frequent morbidity of people with diabetes during the study (P<0.05). Despite a graft occlusion rate after femoropopliteal revascularization significantly higher than in non-diabetic people (P<0.05), diabetic people more often required lower extremity amputations (LEAs) for the same level of bypass (P<0.01). Cumulative limb salvage rates were lower in diabetic patients than in non-diabetic subjects at femoropopliteal (49.2 vs. 89.7%; P<0.001), femorodistal (73.5 vs. 95.2%; P<0.01), and distal reverse (77.9 vs. 87.3%; P<0.05) arterial reconstruction, at the end of the third year, but similar after aorto-iliac reconstruction (93.1 vs. 97.5%). A higher neuropathy score and the presence of foot ulcers were associated to significantly lower limb salvage in diabetic patients (P<0.05), but not in non-diabetic people. Survival rates after 3 years were similar between diabetic and non-diabetic populations after aorto-iliac (93.1 vs. 97.5%), femoropopliteal (97.2 vs. 90.3%), and distal reverse (93.2 vs. 98.1%) revascularization, and slightly lower in diabetic compared to non-diabetic patients after femorodistal revascularization (82.1 vs. 96.3%; P<0.05). CONCLUSION: Although limb salvage after arterial reconstruction is lower in diabetic than in non-diabetic subjects, particularly in those with a higher neuropathy score, this surgical approach can be applied in both diabetic and non-diabetic subjects with otherwise similar outcome.

Lack of hormonal changes in postmenopausal women of equal weight with and without osteoporosis, including relation to time of menopause.

The hormonal variations in postmenopausal osteoporosis are not precisely defined. The duration of the menopause and other factors, such as the weight of the patients, may be of significance. Having a basic criterion of uniformity in weight, sixty postmenopausal women were studied in regard to the following aspects: urinary hydroxyproline, estrone, estradiol, parathyroid hormone, thyroxine, triiodothyronine, thyroid stimulating hormone, cortisol and metacarpal cortical area/total area. They were divided into: Group A: 15 patients with osteoporosis and five years since menopause; Group B: 15 patients without osteoporosis (age-matched with group A); Group C: 15 patients with osteoporosis and more than ten years since menopause; and Group D: 15 patients without osteoporosis (age-matched with Group C). In the group with postmenopausal osteoporosis (A and C) there is a significant increase in urinary hydroxyproline/creatinine and a significant decrease of the cortical area/total area when we compared them with age-matched groups. The hormonal values do not vary significantly among the four groups. Ours results indicate an increase of bone resorption as a cause of postmenopausal osteoporosis. The hormonal variations, if any, cannot be related to basal values.

The plasmatic 11-hydroxy-corticosteroid response in the human to a synthetic octadecapeptide corticotrophin (C-41795-Ba).

The adrenal response as measured by the plasmatic changes in 11-hydroxy-corticosteroid (11-OHCS) concentration following the administration of a synthetic octadecapeptide (C-41795-Ba) was compared in 17 normal young males with that obtained with the commercially available tetracosactrin. C-41795-Ba polypeptide shows a higher potency than tetracosactrin. Its effects are longer lasting when administered intravenously which indicates a significant local inactivation of the polypeptide.

Epidermal growth factor receptors in human breast and endometrial carcinomas.

The incidence and levels of epidermal growth factor receptor (EGFR) were studied in 67 breast tumors and 22 endometrial carcinomas. Estrogen receptors (ER) were also measured in all samples and progesterone receptors (PR) were analyzed in 57 breast samples and 21 endometrial tumors. A high level of EGFR expression is found in both breast and endometrial carcinomas, although the incidence of EGFR content is greater in breast carcinomas. 36% of breast tumors had EGFR at levels 3-49.5 fmol/mg membrane protein, whereas this percentage of positivity was 27% for endometrial tumors. In 51% of breast carcinoma and 73% of endometrial tumors, there was a positive ER content, whereas 53% of breast tumors and 62% of endometrial carcinomas were positive. A clear inverse relationship between EGFR content and ER and PR status has been observed in breast tumors. Our data confirm the previously described inverse correlation between expression of EGFR and estrogen receptors in human breast cancer. We also show here that there is a similar inverse relationship between EGFR content and ER levels in endometrial tumors.

Evidence for a modulatory role of catecholamines on hypothalamic somatostatin in the rat.

The influence of catecholamines (CA) on hypothalamic somatostatin (HPT-SRIF) was investigated in rats by using several drugs which interfere with brain CA metabolism. Depletion of brain CA stores by alpha-methyl-rho-tyrosine (AMT) increased HPT-SRIF, while augmented brain CA levels following L-dopa administration decreased HPT-SRIF content. Blockade of dopamine beta-hydroxylase activity by disulfiram depleted brain noradrenaline (NA) and decreased HPT-SRIF. The selective increase in brain NA stores caused by threo-dihydroxyphenylserine (DOPS) also produced an increase in HPT-SRIF. Increased dopamine (DA) and decreased NA levels after disulfiram + L-dopa (1 h) treatment did not modify HPT-SRIF, whereas unaltered NA and greatly increased DA levels following disulfiram + L-dopa (2 h) treatment produced a drastic reduction of HPT-SRIF. The results suggest that DA and NA exert an influence on HPT-SRIF, supporting previous observations.

Effect of pulse frequency and amplitude of D-Trp6-luteinizing hormone-releasing hormone on the pulsatile secretion of prolactin and LH.

This work analyzes the effect of the pulse amplitude and frequency of a potent LHRH analog, D-Trp6-LHRH, in a perfusion system of isolated rat pituitary cells. To this purpose, we studied the LH and PRL secretion in different conditions: basal secretion, secretion after increasing concentrations of D-Trp6-LHRL (0.001, 0.01, 0.1 and 1 nM) secretion in function of the pulses frequency (2,3, and 4 pulses per h) and amplitude (0.1, 1 and 10 nM). The principal findings were: 1. The basal LH and PRL secretions was pulsatile; 2. The stimulation of LH by the analog was not dose-dependent; 3. When more than 2 pulses per h were administered, a rapid desensitization of gonadotroph to release LH (at 20-30 min) occurred; 4. There was a loss of pulsatility of PRL secretion with an increase in the pulse frequency and amplitude of the D-Trp6-LHRH, which was produced parallelly to the desensitization of the gonadotroph to release LH. In summary, these findings suggest that a rapid loss of pulsatility of the PRL when the D-Trp6-LHRH pulse frequency and amplitude is increased might be due to the early desensitization of the gonadotroph to the analog.

Primary intrasellar germinoma with synchronous pineal tumor.

Germinomas arising within the sella turcica are extremely rare. The association of intrasellar and a pineal region tumours is even more unusual. We report a 30-year-old man with germinomas in the sellar and pineal region.

Evidence of abnormal dopaminergic control of prolactin in patients with hypothalamic and pituitary tumors.

Prolactin secretion was investigated in an attempt to identify the patterns of responses in different types of tumors. Forty four patients were studied: thirty patients with prolactinomas (Group 2); nine patients with growth-hormone (GH)-adrenocorticotropic hormone (ACTH)-secreting pituitary tumors and hypothalamic tumors (Group 3); and five patients with non-secreting pituitary tumors (Group 4). A control group (Group 1) consisted of 60 healthy subjects (30 males and 30 females). All were submitted to testing by nomifensine (Nom), domperidone (Dom) and thyrotropin releasing hormone (TRH). The prolactin levels were measured by radioimmunoassay (RIA). In group 2 the suppression of PRL with Nom and the stimulation with Dom and TRH were significantly lower than in the control group (p less than 0.001). There was no statistically significant difference between groups 2 and 3 in the suppression with Nom. The increase with Dom in group 3 was significantly greater than that in group 2 (p less than 0.001) and less than that in the control group (p less than 0.005). The rise in PRL with TRH was also significantly higher in group 3 than in group 2 (p less than 0.001) and similar to that of the control group. Group 4 gave the same results as the control group to all 3 tests. Our results indicate a dopaminergic irregularity in the hypothalamic and GH-ACTH-secreting pituitary tumors, thus supporting a hypothalamic etiopathogenesis of these tumors. The normality of the GH-ACTH-secreting pituitary tumors and hypothalamic tumor responses to TRH is one more factor in differentiating these from prolactinomas. The normal response of the non-secreting tumors may involve a primary pituitary etiology of these tumors.