Naloxone inhibition of postprandial growth hormone releasing hormone-induced growth hormone release in obesity

The effects of opiate receptor antagonist naloxone on growth hormone (GH) release after growth hormone-releasing hormone (GHRH) administration were investigated, before or after feeding, at 13.00 h, in 20 obese women and in 10 normal women. When GHRH was administered to obese women before a meal at lunch time, the mean peak plasma GH levels were very low, while plasma GH responses significantly increased after feeding. Naloxone, infused at a rate of 1.6 mg/h starting 1 h before GHRH administration (50 micrograms i.v. as a bolus), was capable of inhibiting GH release induced by administration of GHRH after feeding. On the contrary, naloxone did not induce significant variations on the fasting GHRH-induced GH release. In normal women, naloxone did not significantly modify the GH response to GHRH, both before and after lunch. The inhibitory effect of naloxone indicates that in obese women there is an increased opioid activity, which could represent an abnormal response of the gastrointestinal tract to food ingestion.

Evaluation of metabolic status in amiodarone-induced thyroid disorders: plasma coenzyme Q10 determination

In previous works we have demonstrated that Coenzyme Q10 (CoQ10) levels have a significant inverse correlation with thyroid hormone concentration in patients with spontaneous hyper- or hypothyroidism. In order to verify whether this correlation is maintained in patients on long-term amiodarone therapy, in whom thyroid metabolism is altered by the iodine contained in the drug, we have studied 30 patients with thyroid dysfunction induced by chronic amiodarone treatment. We have distinguished four groups of patients: group A (n = 8): patients with true hyperthyroidism induced by drug administration; group B (n = 11): patients with mild hyperthyroid symptoms, but isolated thyroxine increase or dissociation between different indexes of thyroid function; group C (n = 5): patients with normal thyroid hormone levels, but increased TSH levels; group D (n = 6): patients who appeared really clinically euthyroid, with normal thyroid hormone levels and normal TSH response to TRH. In group A patients, plasma CoQ10 levels averaged 0.49 +/- 0.03 micrograms/ml, significantly lower than those in normal subjects and similar to those observed in spontaneous hyperthyroid patients. In group B patients, CoQ10 levels were in the normal range (0.88 +/- 0.10 microgram/ml). In group C patients, CoQ10 levels were lower than those in normal subjects and similar to those of group A patients (0.49 +/- 0.04 microgram/ml); they differed, in regards to CoQ10 values, in comparison with spontaneous primary hypothyroid patients, who had very high levels of plasma CoQ10. Finally, in group D patients, CoQ10 levels were in the normal range (0.77 +/- 0.04 microgram/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

[Male pseudohermaphroditism caused by 17-alpha-hydroxylase deficiency. Personal case reports and a review of the literature]

Adrenal hyperplasia due to 17-alpha-hydroxylase deficiency is coupled with precocious hypogonadism, which causes pseudohermaphroditism in XY subjects and primary amenorrhea in XX subjects. The physiology of gluco- and mineral-corticoid adrenal activity, as well as the biosynthesis of gonadal steroids, is totally altered. We report two cases of XY subjects, identified as females, who came to our observation for primary amenorrhea and exhibited a hypertension with hypokaliemia. We also report a critical review of the literature, with a main attention to differential diagnosis and mineralcorticoid physiopathology, in order to contribute to the knowledge of normal adrenal function and of this enzymatic defect.

Corticotropin-releasing hormone inhibition of gonadotropin secretion during the menstrual cycle

To determine whether corticotropin-releasing hormone (CRH) exerts an inhibitory action on gonadotropin secretion in normal fertile women, the effects of CRH on luteinizing hormone (LH), follicle-stimulating hormone (FSH), and cortisol secretion were studied during the menstrual cycle. CRH had no effect on LH release during the midfollicular phase of the cycle. By contrast, IV injection of 100 micrograms CRH elicited significant decreases in LH concentrations during late follicular (-50%) and midluteal (-52%) phases of the cycle. LH concentrations decreased during the four-hours following injection of CRH and returned to those observed during the control period five hours after injection. Similarly, CRH elicited a significant decrease in FSH secretion during the midluteal phase of the cycle. CRH injection induced an increase in cortisol release during all phases of the cycle. These data demonstrate that exogenous CRH administration results in inhibition of gonadotropin secretion in late follicular and midluteal phases of the cycle. These results suggest that elevated endogenous CRH levels resulting in increased cortisol secretion could contribute to decreased gonadotropin secretion and, thus, disruption of reproductive function during stressful conditions in women.

Prolactin-secreting adenomas: surgical results and long-term follow-up

Transsphenoidal surgery is an efficacious treatment for patients with prolactin (PRL)-secreting adenomas, even if disrupted pituitary-hypothalamic relationships may persist and/or a recurrence of the PRL-secreting tumor can occur. In this paper, we analyze the long-term follow-up of 119 consecutively treated women who underwent transsphenoidal microsurgery for PRL-secreting adenomas. Apparent total removal of the tumor was achieved in 98 patients who had enclosed tumors (58 with Grade-I tumors and 40 with Grade II). In the remaining patients, the removal was considered partial. Persistent normal basal PRL levels were achieved in 61 patients who had apparent total removal of the adenoma (44 with Grade I tumors and 17 with Grade II). Of the remaining 37 patients in whom surgical removal of the adenomatous tissue was thought to be total, 30 had persistent nonevolutive, high PRL levels ranging from 21 to 196 ng/ml, without clinical and radiological signs of tumor regrowth, and 7 with PRL levels ranging from 56 to 560 ng/ml had a recurrence of the PRL-secreting tumor. These data seem to indicate that a slightly elevated postsurgical PRL value does not imply that tumoral tissue is still present. Nontumoral conditions (i.e., a secondary empty sella) could induce functional hyperprolactinemia.

[Growth hormone-releasing hormone. The physiopathologic aspects and its diagnostic-therapeutic use]

The object of the present study is to review all that in the last years has been discovered about growth hormone-releasing hormone (GHRH), in order to point out both its physiopathological characteristics and its possible diagnostic and therapeutic use. In the first section are summarily reviewed the different studies that culminated in 1982 with the identification of three GRF: GRF(1-37)-OH, GRF(1-40)-OH and GRF(1-44)-NH2, the last of which, by immunohistochemical methods, resulted to be similar to the hypothalamic hGHRH. Then we describe the anatomic distribution of GHRH in man, and its mechanism of action at both receptor and postreceptor levels. On the other hand, the control of the GHRH secretion by peptidergic hypothalamic neurons occurs through four principal monoaminergic systems such as dopaminergic, noradrenergic, adrenergic and serotoninergic ones, and also by cholinergic fibers and by endogenous opiates, all acting to cause the release, into the hypothalamo-hypophyseal portal circulation, of GHRH. In the second section is attracted attention on the GHRH as a diagnostic agent in the two diseases that represent the main alterations of the GH secretion: acromegaly and short stature. According to the different studies considered, it may be concluded that GHRH testing has limited diagnostic usefulness in the clinical evaluation of acromegaly, but allows to discriminate acromegalic patients with ectopic production of GHRH from those with pituitary tumors. For what concerns short stature, the results of observation realized both in adult subjects and in children, all with GH deficiency, by exogenous administration of GHRH, have pointed out that the majority of the GH deficiency patients have hypothalamic disregulation, and not a pure pituitary deficiency as it has been supposed before GHRH discovery. In the third section is attracted attention on the GHRH as a therapeutic agent. Its possible use in the therapy of the children with GH deficiency is of considerable interest, above all in relation to the hypothalamic pathogenesis of their short stature.

Corticotropin-releasing hormone inhibition of gonadotropin release and the effect of opioid blockade

We studied the inhibitory effect of exogenous CRH on pulsatile gonadotropin secretion and the role of endogenous opioid peptides in this phenomenon in normal women. To do so, we infused human CRH (100 micrograms/h for 3 h) into 15 normal women during the midluteal phase of their menstrual cycle and studied its effect on both basal (10 women) and GnRH-stimulated (5 women) plasma gonadotropin levels. CRH infusion induced a significant decrease in plasma LH and FSH levels in all women. The decline in plasma LH (62%) was greater than that in FSH (36%). Plasma LH and FSH concentrations returned to basal levels within 30 min after the end of the CRH infusion. CRH infusion did not alter the gonadotropin response to GnRH. We also infused naloxone plus CRH in the 10 women who had received CRH alone during the midluteal phase of a different cycle. Addition of naloxone to CRH (5 women) reversed the LH and FSH inhibition when naloxone was started 1 h after the start of the CRH infusion. When naloxone was started 1 h before CRH infusion (5 women), plasma LH and FSH concentrations did not change. Plasma cortisol increased similarly during both the CRH and CRH plus naloxone infusions; the mean cortisol levels at the end of the CRH and CRH plus naloxone infusions were 497 +/- 40 (+/- SE) and 484 +/- 41 nmol/L, respectively, compared to 240 +/- 14 nmol/L after saline infusion (P less than 0.001). These results demonstrate that in normal women during the midluteal phase of the menstrual cycle, CRH inhibits the secretion of both LH and FSH. The CRH-induced inhibition of gonadotropin secretion is primarily mediated by endogenous opioid peptides, and this effect is not dependent on glucocorticoid levels. We suggest that the disruptive effect of stress on reproductive function in the women could be, at least in part, dependent on decreased gonadotropin secretion induced by elevated endogenous CRH levels.

Periovulatory plasma prolactin response to synthetic growth hormone-releasing hormone in normal women

Following the demonstration of a positive prolactin (PRL) response to growth hormone-releasing hormone (GHRH) in acromegalic and anorexic women, we have injected GHRH (50 micrograms intravenously as a bolus) in normal women during various phases of their menstrual cycle in order to establish whether a positive response was present also in normal subjects. Synthetic GHRH 1-44 elicited a significant increase in circulating PRL levels in eight women studied during the periovulatory phase of the menstrual cycle. In contrast, no significant changes in circulating PRL levels after GHRH administration were found in nine women during the midfollicular phase or in five women during the midluteal phase. A temporal correlation between the midcycle gonadotropin peak and the positive response to GHRH has been observed. Synthetic GHRH elicited the expected increase in GH levels during all phases of the cycle studied. Our data demonstrate that GHRH is capable of stimulating a PRL response in normal subjects and raise the possibility that PRL secretion is regulated by several hormones of hypothalamic origin.

[Hyperandrogenism originating from the adrenal gland. Current observations on a clinical case]

Recent reported data on hyperandrogenisms of suprarenal origin are presented and the case of a 26-year-old woman suffering from hirsutism and secondary amenorrhoea reported. Preoperative hormonal measurement showed very high Dehydroepiandrosterone (DHEA) levels (8,000 ng/ml) and a less dramatic increase in Androstenedione (A) and Testosterone (T), of 3.5 and 1.17 ng/ml respectively. Androgens were uniformly increased following administration of ACTH (250 micrograms for 3h for 2 days) and inhibited by intake of Desamethazone (8 mg/die for 3 days per os). ACTH values were low and failed to increase after insulin-induced hypoglycaemic stimulus. Pelvic echography and laparoscopy showed normal ovaries. A suprarenal scan revealed slight bilateral hyperplasia with irregular trace distribution on the left. CT showed a slight anomaly of the left gland which appeared spherical with convex margins. Unilateral suprarenectomy was carried out and the controlateral gland explored. The removed gland presented a histological picture of "micronodular focal hyperplasia". Treatment was begun with Prednisone and temporary remission of the clinical and biochemical pictures was achieved but one year after the operation androgen concentration was found again to be abnormally increased. The final diagnosis was "Bilateral suprarenal hyperplasia" with initial unilateral involvement. To conclude, this particular hyperandrogenism with ACTH levels at the lower limits of normal and with underlying primary suprarenal hyperplasia may be included among the better known suprarenal hyperplasia syndromes responsible for the Cushing and Conn syndromes.

Treatment of hyperthyroidism due to inappropriate secretion of thyrotropin with the somatostatin analog SMS 201-995

The management of hyperthyroidism due to inappropriate secretion of TSH (IST) includes agents that selectively suppress TSH hypersecretion both in patients with TSH-secreting tumor [neoplastic IST (nIST)] in whom pituitary surgery was unsuccessful and in those with selective pituitary resistance to thyroid hormone action [nonneoplastic IST (nnIST)]. Among such agents, somatostatin administration has proven to be effective in blocking TSH hypersecretion, but its short plasma half-life prevented its use in long term therapeutic trials. The recent availability of a potent and long-acting analog of somatostatin (SMS 201-995, Sandostatin) prompted us to study its effects on serum TSH, alpha-subunit, and free thyroid hormone (FT4 and FT3) concentrations in five patients with nIST and three patients with nnIST. During short term SMS 201-995 administration (100 micrograms, sc, three times daily for 5 days) both serum TSH and alpha-subunit levels decreased in all patients with nIST (mean decrements, -86% and -85%, respectively), with concomitant normalization of serum FT4 and FT3 concentrations. In the three patients with nnIST, this treatment lowered serum TSH levels less well (mean decrement, -47%), although serum FT4 and FT3 levels normalized in one patient. Chronic SMS 201-995 (100 micrograms, sc, every 12 h for 1-7 months) treatment in four hyperthyroid patients (two with nIST and two with nnIST) resulted in a steady euthyroid state in both patients with nIST, with restoration of normal visual fields in one patient. In contrast, in both patients with nnIST, escape occurred after 2 weeks of therapy. We conclude that SMS 201-995 administration is effective treatment for patients with nIST, able to suppress TSH hypersecretion from the adenomatous thyrotrophs and, consequently, to restore clinical and biochemical euthyroidism in such patients. On the contrary, the inhibitory effects of SMS 201-995 on TSH secretion in patients with nnIST are weaker and transient.

Calcium antagonists and hormone release. VI. Effects of a calcium antagonist (verapamil) on the biphasic insulin release in vivo

The present study was designed to investigate the influence of a calcium antagonist (verapamil) on the two phases of insulin release. The present results confirmed our previous studies and in vitro data, showing that the first phase insulin release is not inhibited by a calcium antagonist and strongly indicated that glucose stimulated insulin secretion has two phases of release: (1) the first phase of release, which is independent from extracellular calcium; (2) the second phase of release, which was inhibited by calcium antagonists, is dependent from calcium uptake from an extracellular source.

Differential effects of feeding on the ultradian variation of the growth hormone (GH) response to GH-releasing hormone in normal subjects and patients with obesity and anorexia nervosa

Nutritional status and metabolic fuels are factors involved in the regulation of GH secretion and GH responses to GHRH. The effects of feeding on GHRH-induced GH release were studied in 13 normal women, 14 obese women, and 9 women with anorexia nervosa. GHRH-(1-44) (50 micrograms, iv) was administered at 0900 h after an overnight fast or at 1300 h after a normal meal at 0800 h, and at the same times 45 min after a 800-Cal meal on different days. The mean peak plasma GH responses to GHRH administered before a meal at 0900 h were 52.8 +/- 5.6 (+/- SE) micrograms/L in normal women, 8.2 +/- 1.3 micrograms/L in obese women, and 53.2 +/- 7.7 micrograms/L in anorexic women. When GHRH was administered before a meal at 1300 h, the mean peak plasma GH levels were lower than those at 0900 h; this reduction was -64.2% in normal women, -64.9% in obese women, and -55.8% in women with anorexia nervosa. After feeding, the plasma GH responses to GHRH were blunted in normal women at 0900 h (-60.9%) and 1300 h (-34.6%) compared with the fasting peak responses. In obese women the plasma GH response to GHRH after feeding was increased compared with that when these women had fasted (+60% at 0900 h and +406.9% at 1300 h). Finally, differential effects of feeding were present in anorexic women; the response was lower at 0900 h (-46.4%) and greater at 1300 h (+50.8%). We conclude that there is an ultradian variation in GHRH-stimulated GH secretion and that the responses differ according to nutritional status and body weight.

Plasma prolactin response to gonadotropin-releasing hormone during benzodiazepine treatment

Previously we observed that prolactin (PRL) is secreted in response to gonadotropin-releasing hormone (GnRH) in normal women during the periovulatory phase of the menstrual cycle. Because sedative drugs affect the neurotransmitters involved in the regulation of PRL secretion, we investigated PRL responsiveness to GnRH in pre- and postmenopausal female subjects during prolonged treatment with benzodiazepines (six-60 months). In both pre-and postmenopausal patients who were not on benzodiazepine treatment, GnRH infusion (0.2 micrograms/min for 3 hr) was ineffective in eliciting a PRL response. In six premenopausal women treated with benzodiazepines, basal PRL concentrations were not influenced by the drug in four subjects (range 4.0-15.7 ng/ml) and were slightly elevated in two subjects (23 and 30 ng/ml). In six treated postmenopausal women, basal PRL concentrations were in the normal range (7.5-11.0 ng/ml). GnRH infusion induced a progressive increase in PRL concentrations which reached a peak at 120 min in the premenopausal subjects (mean % SEM increase: 64 +/- 30.5%) and at 60-90 min in the postmenopausal subjects (mean % increase: 110.6 +/- 34.7%). A saline infusion, performed on a separate day during benzodiazepine treatment as a control, did not influence PRL.

Treatment of inappropriate secretion of thyrotropin with somatostatin analog SMS 201-995

Inappropriate thyrotropin secretion (IST) may originate from either neoplastic disease (nIST) or non-neoplastic resistance to thyroid hormone (nnIST). An inhibitory effect of somatostatin on TSH secretion has been documented. In an attempt to elucidate the possible therapeutic effect of this peptide on nIST and nnIST, a study was conducted in 7 such patients. Sandostatin (SMS 201-995) was administered in daily doses of 100 micrograms for several days to 1 month. Four patients with nIST responded with a fall in circulating TSH as well as alpha-subunit with concomitant normalization of free thyroxine and clear symptomatic improvement. In the 3 nnIST patients this effect was considerably less apparent and a partial TSH escape was observed on long-term treatment in 2 cases. The importance of somatostatin and its analogs in the management of thyroid malignancy is stressed.

Sex-related naloxone influence on growth hormone-releasing hormone-induced growth hormone secretion in normal subjects

The effect of opiate-receptor antagonist naloxone on growth hormone (GH) release after growth hormone-releasing hormone (GHRH) 1-44 administration was investigated in ten normal men and 18 normal women during different phases of their menstrual cycle. Naloxone was infused at a rate of 1.6 mg/h in women and 1.6- and 3.2 mg/h in men, starting one hour before GHRH administration (50 micrograms iv as a bolus). On different day sessions, naloxone, GHRH, or saline were administered as controls. Naloxone infusion reduced the GHRH-induced GH release in normal women. The mean % inhibition of peak GH response was 83% during follicular phase, 46.5% during periovulatory phase, and 77.6% during luteal phase. On the contrary, in normal men, both doses of naloxone infusion were ineffective in blunting the GH response to GHRH. Our studies indicate that naloxone infusion was capable of inhibiting GH release induced by direct stimulation with GHRH in normal women, suggesting an opiate-antagonist action at the anterior pituitary level. The absence of such an effect in normal men strongly indicates a sex dependence of naloxone effects and suggests a role of the sexual steroid environment in opioid modulation of pituitary hormone secretion.

Prolactin dynamics in normoprolactinemic primary empty sella: correlation with intracranial pressure

Prolactin dynamic was investigated in 43 premenopausal patients with primary empty sella (PES) diagnosed by pneumoencephalography and CT scan. Only normoprolactinemic patients were included in this study. Basal PRL levels ranged from 4 to 25 ng/ml. PRL responses to TRH (200 micrograms i.v.) and metoclopramide (MCP, 10 mg p.o.) were not significantly different from those in normal subjects, although a trend toward higher responses was present in PES patients. The administration of nomifensine (NOM, 200 mg p.o.) induced a PRL decrease, which was not significantly different from that in normal subjects. However, a sequential stimulation with TRH plus MCP (1 h after TRH administration) induced an exaggerated PRL increase which was significantly different from that in normal subjects. The peak PRL responses after stimulation were not significantly correlated with estradiol levels or FSH/LH ratios in our patients. The influence of body weight was also excluded on the basis of the responses observed in 8 obese control subjects that were significantly lower than in PES patients. Moreover, in 19 patients we studied the intracranial pressure (ICP) through an indwelling catheter inserted into the lumbar subarachnoid space. ICP was normal in 5 patients and elevated in 14 patients. When we compared PRL dynamics in patients with normal or elevated ICP, a significant difference was noted between the percentage of PRL decrease after NOM, that was lower and delayed in patients with increased ICP, suggesting an influence of ICP on neuronal dopamine reuptake. In conclusion, an augmented PRL reserve is present in premenopausal patients with PES. A correlation can be found between ICP and the function of dopaminergic neurons controlling lactotroph cells.

Calcium antagonists and hormone release. V. Effects of a calcium-antagonist (verapamil) on pituitary hormone release in hypersecretory states

Twenty-five patients with various syndromes of pituitary hyperfunction, of tumoral and nontumoral origin, were infused with verapamil (VE), a Ca2+-channel blocker (5 mg/h X 3 h) to assess the calcium dependence of the augmented hormone secretion. In 5 hypogonadal women with elevated gonadotropin secretion, VE produced a marked inhibition of LH (54.6%) and FSH (49.4%) release, comparable to that observed in normal subjects who were infused with VE. In 5 patients with latent or mild hypothyroidism, TSH levels decreased during the VE infusion, and the magnitude of the decrease was directly correlated with the basal levels (r = 0.986, p less than 0.01). In patients harboring a pituitary tumor, differential effects of VE infusion were observed: it induced an inhibition (28.5%) of ACTH secretion in patients with Cushing's disease; in acromegalic patients, no alterations in HGH levels were noted; on the contrary, in prolactinoma patients, a clear PRL increment (47.2%) was present. These experiments confirm that the need for extracellular Ca2+ varies from hormone to hormone and that VE infusion can modify the secretion of pituitary hormone in a hypersecretory state, as well as those hormones which are unaffected by VE infusion in basal condition.

Evaluation of pituitary-thyroid axis response to acute myocardial infarction

We have studied with seriated controls for a period of 9 days 18 patients admitted to our hospital for acute myocardial infarction (AMI). Slight, but non significant variations in thyroidal hormone pattern were observed: slight decrease of T3 and T4 levels, increase of reverse T3 on day 3, low free T4 levels, slight increase of TSH levels until the 3rd day. However, hormonal pattern was clearly different in patients who presented a clinical improvement (group 1a) and in patients who died for AMI (group 1b). In fact, a significant TSH increase was recorded in patients of group 1a; on the contrary, a significant decrease of TSH, T4 and free T4 concentrations was observed for subjects of group 1b, suggesting an inadequate response of pituitary-thyroid axis. In conclusion, the evaluation of thyroid hormones and thyrotropin levels can be of clinical usefulness in the management of patients with AMI. The decrease of plasma T4 and free T4 concentrations, accompanied with low TSH levels, can be associated with unfavorable course of the disease and therefore can be considered a bad prognostic sign.

Evaluation of dopaminergic tone in hyperprolactinemia. III. Thyroid-stimulating hormone response to metoclopramide in differential diagnosis and postoperative follow-up of prolactinoma patients

Recently, it has been shown that patients with a PRL-secreting pituitary adenoma have a greater thyroid stimulating hormone (TSH) release after dopamine (DA)-receptor blockade than normal subjects. We have compared the TSH and PRL responses to metoclopramide (MCP) in normal and postpartum lactating women with those in 28 patients with hyperprolactinemia of different origin. Patients with a PRL-secreting pituitary adenoma were also tested after transsphenoidal removal of the tumor in order to establish the prognostic value of this test in such patients. Following MCP administration, percent increases in plasma PRL levels were greater in normal female subjects than postpartum lactating women. Plasma TSH levels did not increase in postpartum women and had a modest increment in normal subjects. In patients with hypothalamic tumors and empty sella syndrome plasma PRL and TSH levels showed modest or no increases after MCP administration. In ten patients harboring a microprolactinoma, plasma TSH levels showed an exaggerated increment after DA-receptor blockade. Postoperatively, despite normal or borderline PRL levels in the immediate postoperative period, a TSH response to MCP was present (in five patients one to two weeks after the operation, and in five patients one to three years after the operation), suggesting an increased DA activity even in the absence of hyperprolactinemia. In conclusion, the TSH test can easily detect increased DA-activity in patients with a microprolactinoma both preoperatively and postoperatively. It is possible that some patients with increased DA-activity in presence of normal PRL levels and normal PRL responsiveness to stimulation will experience a recurrence of hyperprolactinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolactin dynamics in patients with non-secretin tumours of the hypothalamic-pituitary region

Twenty-four patients with non-secreting tumours of the hypothalamic-pituitary region, diagnosed by radiographic procedures and confirmed at surgery, were examined before and after the surgical treatment to establish a correlation between Prl responsiveness to dynamic tests and the location of pathological tissue. Three groups of patients were identified. In 10 patients with an intrasellar tumour (group I), Prl had a positive response to TRH, metoclopramide (MCP), and nomifensine (NOM), both pre- and postoperatively. In 4 patients with tumours located entirely in the hypothalamus (group II), Prl responded to TRH, but remained unresponsive to MCP and NOM. Only a partial normalization of the Prl responses was obtained after surgery. Finally, 10 patients had an intra- and extrasellar tumour (group III). In 8 of them Prl responded to TRH, but the increment was lesser than that observed in hypothalmic tumours. Prl did not respond to MCP and NOM. After surgery, Prl responsiveness reappeared in some patients (6 after TRH, 4 after MCP, 3 after NOM). In 2 patients with extensive pituitary damage, Prl did not respond to all dynamic tests pre- or postoperatively. In conclusion, Prl dynamic tests are a reliable tool for studying the altered control of Prl secretion in these patients, since plasma Prl stems from only normal lactotropes surrounding the tumoural tissue. The location of the tumour has a key role in influencing the pattern of Prl response to direct and indirect dynamic tests.

Multicentric experience on the acute effect of nomifensine in hyperprolactinemic women

The inhibitory effect of nomifensine ( Nom ; 200 mg orally) on prolactin (PRL) secretion was studied in 15 subjects with puerperal hyperprolactinemia and in 59 pathologic hyperprolactinemic women. The latter were grouped as follows: i) patients with surgically proven PRL secretory pituitary adenomas (proven tumors; 27 cases); ii) patients presenting radiological signs of sella indicative of a pituitary tumor (presumptive tumors; 10 cases); iii) subjects with non-drug induced hyperprolactinemia (hyperprolactinemia of uncertain etiology; 22 cases). A mean PRL fall of 30% or more of baseline hormone levels in samples collected within the 120-240 min post-treatment interval was adopted to define responsiveness to Nom . In 24 out of 27 subjects with proven tumors and in 9 out of 10 subjects with presumptive tumors Nom did not induce significant variations in PRL secretion. In only 11% of the patients with surgery-confirmed or highly suspected tumors a hormone decrease greater than 30% was observed. In addition, 13 subjects with hyperprolactinemia of uncertain etiology did not respond to Nom administration. In 5 of these, additional data suggesting the existence of an adenoma were collected. Finally, 3 out of 9 Nom -responder patients presented either a polycystic ovary syndrome or transitory hyperprolactinemia. The finding that hyperprolactinemic women, who did not show clinical or radiological signs of a tumor and patients with highly presumptive or proven pituitary tumors may present comparable responses to Nom , suggests that this pattern may be indicative of an early manifestation of a PRL-secreting adenoma which has yet to evolve. The follow-up of Nom -non-responder hyperprolactinemic subjects who did not show clinical signs of harboring a tumor, is therefore advisable.

Postoperative evaluation of dopaminergic tone in prolactinoma patients. II. Plasma thyrotropin response to metoclopramide

In 24 patients who had a PRL-secreting pituitary adenoma, diagnosed by pituitary dynamic function tests and CT scan, and confirmed at surgery, the TSH response to a dopamine (DA)-antagonist drug, metoclopramide (MCP), was studied pre- and postoperatively to elucidate whether altered DA tone was present and related to hyperprolactinemia. Preoperatively, a TSH response to MCP occurred in 18 patients. Plasma TSH levels did not increase after MCP in 5 patients who had a macroprolactinoma and in 1 patient with a microprolactinoma located just beneath the diaphragm of the sella turcica. Postoperatively, in all patients who had a prolonged clinical remission and normalization of PRL dynamic tests TSH did not respond to MCP (9 of 24 patients). In 4 patients who had normal or borderline PRL levels in the immediate postoperative period, the TSH response to MCP disappeared, but became evident later together with progressive elevation of PRL levels. TSH increases after MCP occurred in all patients who had abnormal PRL levels after surgery, except in 2 patients with a macroprolactinoma infiltrating the neighboring structures. In conclusion, these results confirm the existence of increased DA tone in patients with a prolactinoma. However, the presence of an increased TSH response to DA antagonist drugs could be masked in patients who had large tumors or tumors located just beneath the sellar diaphragm. The TSH test after MCP administration can readily detect increased DA tone in the postoperative period even when PRL levels remain slightly elevated or borderline.

Relationships between intracranial pressure and diurnal prolactin secretion in primary empty sella

The role of the intracranial pressure (ICP) in the development and/or maintenance of the primary empty sella has been evaluated by recording the ICP during sleeping and waking periods in 11 women who had this syndrome. Concomitantly, plasma PRL levels, measured at 2-hour intervals during a 24-hour period, were compared with the changes in ICP. Daily PRL variations were also measured in 5 normally cycling and 5 postmenopausal women. ICP was abnormally increased in 8 patients with PES. In 3 of them, increased values were recorded during waking and sleeping periods, while in 5 subjects abnormal values were observed only during sleep. In the remaining 3 patients the ICP was normal in all conditions tested. 8 patients with elevated ICP presented an absent or blunted nocturnal PRL increase. In 3 patients with normal ICP, the circadian periodicity of PRL was preserved. The normalization of ICP obtained in 4 patients by a surgical shunting procedure was accompanied by the return to normal of the circadian PRL periodicity. Our observations demonstrate that the finding of a normal ICP during wakefulness is not sufficient to rule out an actual increase in ICP, since a rise in the CRF pressure can occur during sleep. Our data also demonstrated a correlation between an abnormal rise in ICP and an absent or blunted nocturnal increment in PRL secretion.