The effects of mazindol, an anorexiant, on the secretion of anterior pituitary and adrenocortical hormones were examined in healthy male volunteers and in patients with Addison's disease. In healthy male volunteers, significant elevations in plasma ACTH, β-endorphin, β-lipotropin and growth hormone were induced by mazindol administration, though no changes were observed in plasma thyrotropin, luteininzing hormone, follicle-stimulating hormone or prolactin. Plasma ACTH increased in patients with Addison's disease, too. In addition, plasma cortisol increased, without a change in the plasma aldosterone levels after mazindol administration to normal subjects.

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We have reported that iv administration of conjugated estrogens results in no significant change in the plasma LH-RH level during the negative feedback phase of LH, suggesting that estrogen does not suppress LH by decreasing hypothalamic LH-RH. To determine the site of estrogen action during the negative feedback phase, we studied the pituitary response to a small amount of LH-RH after estrogen administration in normal cyclic women in the midfollicular phase. The pituitary responses to an iv bolus of 2.5μg of synthetic LH-RH were evaluated by measuring serum LH and FSH 2 h before and 8 h after administration of 20mg of conjugated estrogens (Premarin). The mean levels of serum LH and FSH were significantly (p<0.05) decreased 8 h after the injection. The peak responses of LH and FSH to LH-RH were also significantly (p<0.05) reduced after Premarin administration. These findings suggest that the negative feedback effect of estrogen on gonadotropin secretion is caused by its direct suppression on the pituitary response to LH-RH.

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Prostaglandins (PGs) may play an important role on cervical ripening in late pregnancy, namely cervical dilatation and softening. To investigate this, arachidonic acid metabolites of cervical tissue and endocervix were studied. To separate and identify the metabolites, silicic acid chromatography, thin layer chromatography, reversed phase chromatography, gas-liquid chromatography and GC-MS were used. In cervical tissue, arachidonic acid was converted to 6-ketoPGF_1α, PGF_2α, PGE₂, thromboxane B₂, and 12-HETE. In endocervix, arachidonic acid was converted to PGF_2α, PGE₂, thromboxane B₂, 12-hydroxy-5, 8, 10-heptadecatrienoic acid, and 12-HETE. There was no relation between the arachidonic acid conversion rate and the Bishop score (points of cervical ripening).

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The effects of cholecystokinin octapeptide (CCK) and bombesin on rat plasma growth hormone (GH) and prolactin (PRL) levels were investigated with the animals under urethane anesthesia. Intraventricular administration of both CCK (0.3 μg) and bombesin (2 μg) completely suppressed the GH secretion induced by FK 33-824, chlorpromazine (CPZ) or prostaglandin E₂ (PGE₂). Both peptides also completely suppressed the PRL secretion induced by FK 33-824 or PGE₂, and partially that induced by CPZ, but not that induced by domperidone. The intravenous administrations of CCK and bombesin had no or lesser potency in inhibiting the stimulated GH or PRL releases. These results indicate that the CCK and bombesin act much in the same manner to inhibit GH and PRL. These peptides may suppress the GH and PRL secretions via a hypothalamus-related action

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The effect of exogenous arachidonic acid on insulin secretion was investigated in a perifusion system using isolated hamster pancreatic islets. Exogenous arachidonic acid (10, 20, 50, 100 μg/ml) markedly stimulated glucose-induced insulin release. The enhancement of insulin release by arachidonic acid was completely inhibited by the cyclooxygenase inhibitor, sodium salicylate (0.5mg/ml). In contrast to this, lipoxygenase inhibitor, nordihydroguaiaretic acid (10^-4 M), enhanced arachidonic acid-induced insulin secretion. Arachidonic acid hydroperoxide inhibited glucose-induced insulin release. Exogenous PG E₂ (10^-5 M) potently elevated immunoreactive insulin (IRI) values throughout perifusion.
These results suggest that the enhancement of insulin release by exogenous arachidonic acid is derived from newly synthetized prostaglandins and on the other hand, activation of the lipoxygenase pathway inhibits arachidonic acidinduced insulin secretion by decreasing the synthesis of prostaglandins.

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We examined the possibility that abnormalities of growth hormone (GH) release in cirrhotic patients were related to a reduction in the ratio of branched chain amino acids (BCAAs) to aromatic amino acids (AAAs) in plasma.
The intravenous infusion of 250 μg of thyrotropin-releasing hormone (TRH) caused a significant rise in plasma GH greater than 5 ng/ml and more than twice as much as the basal levels in 7 out of 15 patients (responders) but an insignificant rise in the remaining patients (non-responders). The difference in the basal GH level was not significant. The oral glucose load suppressed plasma GH in all of the normal subjects and 6 of 7 non-responders, while it was elevated in 6 of 7 responders and one of the non-responders. The ratio of BCAAs to AAAs in the plasma of cirrhotic patients was 1.21±0.38, which was significantly lower than that of normal sub jects (3.31±0.42, p<0.01). In addition, there was a significant difference between responders and non-responders in the ratios (0.96± 0.22 vs 1.42±0.36, p<0.05). An inversely significant correlation (p<0.05) between the ratios of BCAAs to AAAs in plasma and the peak levels of GH after TRH injection was observed when all subjects were combined, but no correlation was found between the ratios and the peak levels of GH after oral glucose loading. There were also significant correlations (p<0.01) between the ratios and various parameters including the serum albumin, cholinesterase and indocyanine green disappearance rate constant (KICG).
These data suggest that the derangement of the central monoaminergic mechanism related to the decreased ratio of BCAAs to AAAs might participate in the abnormal responses of GH to TRH and glucose load often observed in patients with liver cirrhosis.

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Oxytocin receptors (OXT-R) and prostaglandin F_2α receptors (PGF_2α-R) in human myometrium, amnion and decidua during pregnancy and at parturition were examined in an effort to clarify their role in the initiation and maintenance of uterine contractions. The number of binding sites for OXT in myometria showed an increase as gestation advance (Ist trimester v.s. at term ; 205+90 v.s. 671 ± 98 fmol/mg protein, N=5, p<0.01), and a rapid decrease following the onset of labor (254 ±60 fmol/mg protein, N=5, p<0.02). On the other hand the number of PGF_2α-R, remained unchanged throughout pregnancy and in labor. This myometrial PGF_2α binding capacity was approximately 1/20 to 1/30 that of the OXT binding, while binding affinity was almost equal. The OXT-R both in amnion and decidua, which was 1/6 to 1/7 that in myometrium, showed no significant changes throughout pregnancy or after the onset of labor. Binding affinity for each tissue was almost the same and appeared to increase towards term but no statistical significance was detected. Present data confirmed the presence of OXT as well as PGF_2α receptors in the three functionally distinct entities of pregnant human uterus ; myometrium, amnion, and decidua. Among the components, the OXT binding increased only in the myometrium during pregnancy, suggesting this tissue specifically responds to OXT. In contrast, there was a constant binding in myometria for PGF_2α. Further, in in vitro incubation of the tissue with PGF_2α, the predominant change observed was an increase in OXT-R binding affinity. This change was observed in all these specimens at term before labor. Since human uterine contractions can be induced effectively with PGF_2α throughout pregnancy while induction by OXT is only feasible near term, our observations seem to explain the differences in efficacy of the two uterotonic compounds at different stages of pregnancy.

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The effects of hyperprolactinemia on the release of immunoreactive luteinizing hormone-releasing hormone (LH-RH) and luteinizing hormone (LH) in response to iv injection of 20 mg conjugated estrogens (Premarin (R)) were studied. Five normal cycling women were injected with Premarin on the morning of the 7th day of the first cycle (control cycle), and then the plasma levels of LH-RH, LH, and prolactin (PRL) were determined every 8 to 16 hours for 72 h. Two months later, the same women received 200 mg of oral sulpiride daily for 8 days from the 3rd day of the cycle (sulpiride treated cycle), and then the same protocol as in the control cycle was applied.
Mean (± SE) plasma levels of PRL on day 7 in the sulpiride treated cycle were significantly higher than those in the control cycle (118 ± 24 ng/ml vs. 14 ± 4 ng/ml, p <0.001). After estrogen injection, the mean percent increases in immunoreactive LH-RH at 32h (control: 71 ± 38% vs. sulpiride: 6 36%) and 40 h (154±38% vs.-5±21%) and in LH at the 48 h (175±89% vs. 57±57%) and 56 h (99 32% vs. 7 ± 21%) were significantly (p <0.01 or p <0.05) suppressed in the sulpiride cycle.
These data suggest that the impaired positive feedback effect of estrogen on LH-release in hyperprolactinemic anovulatory women may be caused, at least in part, by disturbed LH-RH release.

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We found transient hyperthyroidism in the course of hydrocortisone withdrawal in two patients who had undergone unilateral adrenalectomy to resect cortisol-hypersecreting adenoma. A 38-yr-old woman showed clinical thyrotoxicosis 3 months after the operation. Serum T₄, T₃ and TBG levels were 11.9μg/dl, 310 ng/dl and 16.5μg/ml, respectively. She was given methimazole (MMI) mg/day for 4 weeks. After the cessation of MMI treatment, she eventually recovered to the euthyroid state. The other patient, a 34-yr-old man showed mild clinical symptoms of hyperthyroidism 2 months after the operation. Serum T₄, T₃ and TBG levels were 10.4 μg/dl, 240 ng/dl and 14.5μg/ml, respectively. In this case, no antithyroid drug was given. Two to three months the onset of hyperthyroidism, he returned to the euthyroid state spontaneously. We carefully eliminated the possibilty of factitious thyrotoxicosis in cases. They had neither neck pain nor fever. Both had low radioactive iodine uptake by the thyroid. Therefore, we diagnosed them as painless thyroiditis induced after the resection of hypersecreting adrenal adenoma.

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To examine the behavior in the receptor-acceptor system of glucocorticoids of different biopotencies, the stability of receptor complexes of dexamethasone (Dex), prednisolone (Pred) and corticosterone (Cort) in cytosols, nuclei and nuclear extracts from the rat liver was compared. Receptor complexes bound to these ligands were relatively stable at 0°C, but at 25°C a rapid liberation of ligands was observed. However, differences in the rate of temperature-dependent decay of these receptor complexes were obvious; the Dex receptor complex was the most stable, the receptor complex bound to Cort liberated the ligand most rapidly and the stability of the Pred-receptor complex was the intermediate of these two. The addition of molybdate and dithiothreitol stabilized the receptor complexes in cytosols but these agents accelerated the liberation of ligands from the complexes in nuclei and nuclear extracts. Among the factors examined, only bovine serum albumin decreased the rate of decay in the nuclear-bound receptor complexes. From these observations, it appears likely that different mechanisms may contribute to the dissociation of ligand from receptor complexes in cytosols, nuclei and nuclear extracts.

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It has been suggested brain serotonin (5HT) plays a role in regulation of the hypothalamic-pituitary-adrenal system, although none of the experimental approaches so far reported has produced unequivocal results, mainly on account of the static tissue 5HT level or the known effects of drugs being employed in interpretation of their data. The present study in rats of the possible feedback influence of glucocorticoids on the brain 5HT was designed to analyze the dynamic turnover of its metabolism.
Intracisternal injection of corticosterone (COR) caused no significant changes in 5HT content but increased its turnover dose-dependently in the cortex-cerebellum and the rostral brain stem including the hypothalamus, and lowered the serum COR level at doses less than 5.0μg/kg, reducing its effect with increasing doses. Intracisternal or intraperitoneal administration of miliary doses of dexamethasone (DEX) decreased 5HT turnover in the same brain portions. The effects of glucocorticoids on the brain 5HT metabolism were more potent when injected intracisternally, especially onto the rostral brain stem.
Although COR and DEX played controversial roles, the present results suggest that adrenal glucocorticoids may directly act on brain 5HT metabolism and there may be a feed-back relation between adrenal glucocorticoid and brain 5HT.

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Twenty-four adult female Sprague-Dawley rats (3 from each of 8 litters), showing 4-day cycles, were used in the present study. Aqueous extracts of pools of 6 pituitary glands in each cycle date were fractionated with a column isoelectrofocusing (IEF) technique, pH range of 3.5-10. Biological and immunological LH activities were determined by an in vitro bioassay and a radioimmunoassay, respectively, in the original aqueous extracts of the pituitary glands and in the fractions separated by IEF.
Pituitary content of LH was the highest in the proestrus before the preovulatory LH surge (1243.7±67.8μg NIAMDD rat LH-RP-1/pituitary gland for the biological activity). In the estrus, after the LH surge, it was reduced to 688.9±51.2μg/pituitary gland. The decreased pituitary content was recovered to the level in the proestrus during the metestrus and the diestrus (1047.0±53.8 and 1173.0±58.5μg/pituitary gland, respectively). Rat LH in the pituitary aqueous extracts was separated into multiple subpopulations in terms of pI values by IEF; i.e. Subpopulations A (pI=10.3), B (9.3), C (9.0), D (8.7), E (8.3), F (neutral LH), and G (acidic LH). Among them the most predominant one was Subpopulation A throughout the estrous cycle. Subpopulations A, B and C exhibited statistically significant cyclic changes as was observed in the pituitary LH content, whereas the remaining ones stayed at constant levels during the cycle. The highest ratio of biological to immunological LH activities (B/I ratio) was obtained in Subpopulation A (6.41), followed by G, C and B (5.15, 4.24 and 3.99, respectively). Depressed B/I ratios were revealed in D, E and F (2.59, 1.86 and 3.07, respectively).
High alkaline LH subpopulations, i.e. A, B and C, preserving high biological potency and showing cyclic changes during the estrous cycle, seem to be the releasable types of the hormone and to be mainly discharged for the preovulatory LH surge. Although characteristic features of other types of the hormone are not known, it is possible that one of them, presumably the acidic LH, might be the newly-synthesized type of the hormone, which might attain releasability by certain molecular modifications involving a shift in the pI value.

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The effects of bromocriptine, a dopamine agonist, and cyproheptadine, a serotonin antagonist, on basal and corticotropin-releasing factor (CRF)-stimulated ACTH release were investigated in a 40-year-old female patient with Nelson's syndrome.
Oral administration of either bromocriptine (2.5mg) or cyproheptadine (8mg) caused a marked drop in plasma ACTH levels. Intravenous administration of synthetic ovine (o) CRF (50μg) produced an exaggerated response of plasma ACTH. Short-term (3-week) treatment with either bromocriptine (7.5mg/day) or cyproheptadine (12 mg/day) resulted in a marked suppression of basal ACTH release. Furthermore, a blunted response of plasma ACTH to oCRF was observed after short-treatment with either drug. However, after a longer period of treatment with cyproheptadine (18-week), plasma ACTH levels rose again and hyperresponsiveness to oCRF was restored to the pretreatment levels.
These data indicate that synthetic oCRF is a potent secretagogue for ACTH release in a patient with Nelson's syndrome. It is suggested that bromocriptine and cyproheptadine are effective drugs in reducing basal and CRF-stimulated ACTH release, possibly acting at the pituitary level in this case. However, the apparent refractoriness after chronic treatment with cyproheptadine may limit its therapeutic use in the present case.

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A subpopulation of lymphocytes forming rosettes with autologous erythrocytes was studied on peripheral blood and thyroid tissues obtained from the patients with various thyroid diseases.
The mean (±S. D.) percentage of autorosette-forming cells (ARFC) was 10.1 (±5.5)% in the peripheral blood from patients with hyperthyroid Graves' disease, which was higher than that in nomal subjects (5.6±2.8%), while the levels of ARFC in the peripheral blood from euthyroid patients with Graves' disease under treatment and Hashimoto's thyroiditis did not significantly differ from the normal level. The mean percentages of ARFC in the thyroid tissues from patients with Graves' disease and Hashimoto's thyroiditis were 14.7 (±8.5) and 13.3 (±7.8)%, respectively, which were higher than those in the peripheral blood from the same patients. Most of these cases with abnormally high levels of ARFC were accompanied with the abnormally low T cell to B cell ratios. The microscopic examination of the cytological materials from these patients showed an increased number of large stimulated lymphoid cells or lymphoblasts as compared with those who had few ARFC. These results suggest an increase in an activated T cell subset in the circulation and/or in the thyroid tissue, which is probably caused by active immune response to some stimuli.

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Human low molecular weight kininogen was partially purified and applied to the measurement of human glandular kallikrein as a substrate. The prepared human low molecular weight kininogen did not contain any significant amounts of kinin generating or destroying enzymes. When ethanol was added to the assay tube to stop the enzyme reaction, the substrate was almost completely removed from the incubation solution. Moreover, less than 1.25% ethanol had no effect on the kinin radioimmunoassay. These data suggest that the measurement of generated kinin can be done directly after the addition of ethanol. In this assay system, control tubes were unnecessary since the small volume of the urine samples (0.5 to 2.0 nl) contained negligible amounts of endogenous kinin. In a comparison of the availability as a substrate for human urinary kallikrein among human, dog and bovine low molecular weight kininogens, the enzyme activity was 5 or 100 times as high in the human substrate as in the dog and bovine substrates, suggesting that a human substrate is best for the human enzyme. A significant correlation was found between our previous method using bovine substrate and this method for human urinary kallikrein activity. In both methods, urinary kallikrein excretions were significantly lower in patients with essential hypertension and higher in those with primary aldosteronism, respectively.
This simple, specific and sensitive kininogenase assay system seems to be very useful for investigating the physiological or pathophysiological role of the renal kallikrein-kinin system in hypertensive and renal diseases.

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Neonatal injections of 20μg 17β-estradiol (E₂) induced persistent proliferation and cornification of the vaginal epithelium in adult ovariectomized C57 Black/Tw mice. However, permanent vaginal changes were prevented by various retinoids when, simultaneously with E₂ treatment, the animals were given injections of 100μg daily dose of retinol, retinol acetate, retinal or of 200μg daily dose of retinol palmitate (RoP). Neonatal injections of a 100μg daily dose of RoP had no preventive effect on the occurrence of E₂-induced permanent vaginal changes. This finding suggests that the preventive effect of RoP is weaker than that of other retinoids showing approximately the same degree of prevention. Combined treatment with E₂ plus retinoic acid (even a small dose of 20μg) had such a toxic effect on newborn mice that they died within 7 days after birth, while the animals given neonatal injections of 20μg retinoic acid alone survived until the termination of the experiment.

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A case of male hypogonadism after removal of macroprolactinoma was successfully treated with gonadotropin. A 35-year-old man treated surgically for pituitary adenoma had elevated plasma prolactin and impaired pituitary function after the operation. He was on replacement of hydrocortisone, levothyroxine and testosterone depot along with bromocriptine. Normal plasma testosterone levels were achieved with HCG, 3, 000 IU three times a week. The addition of 75 IU of FSH daily restored spermatogenesis and the sperm count reached the fertile range at the 11th month. Doses of HCG and FSH were cut in half at the 10th month without affecting the plasma testosterone levels. His wife was impregnated at the 12th month and gave birth to a normal baby girl.

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Monolayer islet cells prepared from neonatal rat pancreases were cultured in media with 5.5 mM glucose alone or further supplemented with 5 mM 3-amino-3-deoxyglucose (3A3dG) for a total of 7 days. After culture for 7 days, 3A3dG-supplementation maintained the recovery of insulin released into the medium during the last 2 days of a 7-day culture at a level 2.9 fold higher than at day O. Similarly, the insulin content of the cells was significantly higher than the initial level at day 0 (2.8-fold) and that of the cells grown in medium with glucose alone (4.5-fold). The maximum secretory responses to glucose (2.8-16.7 mM), leucine (2.5-10 mM) and 2-ketoisocaproate (2.5-10 mM) were several times as high as the initial. Further, 3A3dG caused a selective deletion of fibroblasts mostly consisting of endocrine cells. In these monolayer cells, either the cAMP response to glucose or the cellular cAMP content were significant. In conclusion, it is suggested that the beneficial effect of 3A3dG may be associated with an increase in either the oxidative catabolism of amino acids or the activity of adenylate cyclase in the B cell.

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Serum luteinizing hormone (LH) of cynomolgus monkeys was measured by radioreceptor assay (RRA). The assay system consisted of 100μl of standard or unknown samples, 100μl of a receptor preparation and 100μl of ¹²⁵I-LH (LER-960). Dispersed interstitial cells of mature rat testes were suspended in Tris-HCl buffer containing MgSO₄ (5 mM), bovine serum albumin (0.1%) and sucrose (0.3 M) and used as the receptor preparation. ¹²⁵I-LH was dissolved in the same buffer. The incubation was carried out at 37°C for 2 to 3 hr. The nonspecific inhibitory effect of sera in the radioreceptor assay system was compensated for by using LH-free diluent prepared by heat treatment of pooled sera. Validation of the assay demonstrated good reliability in terms of accuracy, precision and sensitivity (equivalent to 3.1μg LER-907/ml of serum). Recovery experiments were performed by adding known amounts of cynomolgus pituitary LH to the normal serum and mean recovery and the standard deviation of the mean was 86±13%. The intra- and inter-assay coefficients of variation were 7 and 9%, respectively. By using this RRA system, cyclic changes in serum LH during the menstrual cycle were determined in three adult female cynomolgus monkeys. These results indicate that this RRA system is useful in measuring serum LH in female cynomolgus monkeys.

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