The female Afgan pika is known as a species of copulatory ovulators exhibiting persistent estrus unless copulatory stimuli are employed. The plasma LH concentration rose quickly after copulation, peaked at 6h and descended thereafter until 12h. Before copulation (estrus), immunoreactive LH-containing cells of the pituitary in this species were filled with numerous large electron dense secretory granules, but the Golgi apparatus and the granulated endoplasmic reticulum were not well developed. One hour later the stainability of the cells was faint, their secretory granules were malls in size and in number, and were of low electron density. These alterations were the most predominant at 12h after copulation. No exocytotic extrusion of secretory granules was obserbed throughout the experiment.

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Changes in the immunoreactivity of pituitary luteinizing hormone (LH) cells and in their fine structure were studied in 4-day-cyclic female rats along with the radioimmunoassay of pituitary and serum LH.
Pituitary LH increased during diestrus (DE) and in early proestrus (PE) to a maximal level at noon of PE, followed by a marked decrease by 2100h PE. Serum LH stayed at low levels in estrus (E) and in DE, while they displayed a significant increase at PE. Light microscopic immunocytochemistry distinguished intensely and weakly stained cells using rat LHβ antiserum. The populations of intensely stained cells were 80% at PE, 30% at E and 75% at DE. This suggests that all of the LH cells do not secrete LH Synchronously on the afternoon of PE. Immunoreactivity of LH cells was related to the amount of secretory granules stored in the cells as determined by the superimposition technique. Analysis of the LH storage site by the protein A-gold method confirmed that the small secretory granules, which accumulated in LH cells at DE or PE, certainly contain LH. At least two LH cell types were distinguished: one is the oval or polygonal cell with flattened rER numerous mitochondria, abundant small secretory granules (about 200nm), a well deveoped Golgi complex, and a round nucleus. The other has similar structural characteristics along with large secretory granules which are more than 300nm in diameter. At noon of PE almost all of the LH cells were the first type while the second ones were mainly found at DE or E. The relationship of these LH cell types to the male gonadotrophs is discussed.

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The preventive effect of impriflavone, 7-isopropoxy-isoflavone, on the development of experimental osteopenia in rats was studied. Male Wistar rats (4 weeks old) on a calcium restricted, vitamin D deficient diet were given a daily oral administration of ipriflavone. The administration of ipriflavone (100 mg/kg BW/day) for 40 days significantly inhibited a decrease in the cortical thickness (14.0±1.6 vs. 17.1±2.9%, mean±SD, p<0.05) and bone calcium content (62±4vs. 67±2mg, p<0.05) in the femora of rats induced by a mild calcium restricted (0.3%), vitamin D deficient diet. This compound did not affect serum calcium levels in this condition. But a dose of 20mg/kg BW/day of ipriflavone was insufficient to inhibit a decrease in bone calcium content. In rats fed on a more severe calcium restricted (0.03%), vitamin D deficient diet, the administration of impriflavone (100mg/kg BW/day) did not significantly affect the cortical thickness or calcium content. Intestinal calcium absorption measured by the in situ loop method was not significantly different between rats fed with a severe calcium restricted (0.03%), D deficient diet with or without ipriflavone (20 or 100mg/kg BW/day) These results demonstrate that the new compound, ipriflavone, partially prevents bone calcium loss induced by a mild calcium restricted (0.3%), vitamin D deficient diet in rats. However, the precise mechanism of action of this compound remains unknown.

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The interaction between gonadotropin and prolactin (PRL) on ovarian steroidogenesis as well as c-AMP production was studied in rat ovaries. Ovaries obtained from adult female Wistar rats in a morning of proestrus were chopped into 30-40 pieces and subjected to short term incubation studies using various buffers. HCG-stimulated c-AMP, estradiol (E₂), progesterone (P) secretions were suppressed in a dose-dependent manner by ovine (0) PRL in a plain Gey-Gey (G-G) buffer. Addition of 3-isobutyl-1-methyl-xanthine (IBMX) increased c-AMP accumulation as well as E₂ and P secretions. Deletion of Ca⁺⁺, from the IBMX buffer stimulated c-AMP production, but suppressed steroid secretion. The inhibitory effect of PRL on E₂ and P was not demonstrated in IBMX buffer at any Ca⁺⁺ concentration examined despite suppression of c-AMP production. In conclusion, it was demonstrated that 1) PRL inhibited gonadotropin-stimulated production of E₂ and P by inhibiting c-AMP production. 2) IBMX stimulated accumulation of c-AMP, E₂ and P and counteracted with the antigonadal effect of PRL. 3) Ca⁺⁺ inhibited c-AMP accumulation but stimulated E₂ and P secretions. 4) The data suggested that PRL exerts its antigonadal effect through an inhibition of adenylate cyclase action in a manner similar to that of Ca⁺⁺.

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We studied the effect of the state of the thyroid on T4 monodeiodination in the rat placenta, and it was compared with those in the liver and kidney. The tissues, maternal serum, and amniotic fluid were obtained from pregnant rats. The tissues were homogenized in cold 50 mM Tris-HCl buffer, pH 7.5. The homogenate (1mg protein) was incubated at 37°C for 60 min with 1μg T₄ in the presence of 5mM DTT. The T₃ and reverse T₃ generated in the reaction mixture were extracted into cold ethanol and measured by RIAs. The conversion of T₄ to reverse T₃ in rat placenta was not significantly changed in MMI-induced hypothyroidism or T₄ induced hyperthyroidism. On the other hand, conversion of T₄ to T₃ in the liver and kidney were changed in parallel with the thyroid state. The concentration of reverse T₃ in the amniotic fluid was increased in accordance with the increase in the maternal serum T₄ concentration. These results indicate that the placental T₄ inner ring deiodination is not affected by the thyroid state, and that the change in the amniotic fluid reverse T₃ concentration in this study is mainly dependent upon the change in maternal thyroid function.

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Functionally active or regressing corpora lutea were harvested from pseudopregnant (psp) rats between days 5-8 of psp or day 15 of psp, respectively. They were enzymatically dispersed and cultured for 24 h to assess progestins in the medium and 20α-hydroxysteroid dehydrogenase {20α-HSD, catalyzing the conversion of progesterone to 20α-dihydroprogesterone (20α-OH-P)} activity in the cell. Though the active luteal cells retained low 20α-HSD activity, they secreted 6-7 times more 20α-OH-P than progesterone as the regressing luteal cells did. There was no significant difference between the total amounts of progestins in the 2 groups.
When increasing doses of pregnenolone were added to the media, progesterone secretion from the active luteal cells was promoted and the progesterone to 20α-OH-P ratio became comparable to the circulating progestins ratio during the mid-luteal phase. In contrast, from the regressing luteal cells only 20α-OH-P secretion was promoted.
These results indicate that an insufficient precursor supply results in the catabolism of a large part of synthesized progesterone before its release from luteal cells and suggest the presence of a high affinity but low capacity 20α-HSD in active corpora lutea.

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Peripheral plasma somatostatin-like immunoreactivity (SLI) was estimated in non-extracted plasma using a specific somatostatin-14 (SS-14) antiserum. The basal plasma SLI level in healthy subjects (n=18) was 43±2.9pg/ml (mean±SE) and rose significantly to 8.3±2.7, 7.3±1.1 and 5.8±2.1pg/ml above the mean basal level 20, 30, and 40min after a mixed meal, respectively (P<0.05). Basal plasma SLI levels in diet (n=8), sulfonyl urea (n=8), and insulin groups (n=8) of non-insulin-dependent maturity onset diabetics (NIDDM) were 50±1.6, 59±4.5, and 74±5.8pg/ml, respectively. The basal levels for patients with NIDDM were significantly higher than those for healthy subjects (P<0.05). No significant increases in plasma SLI were observed after a mixed meal in any group of NIDDM subjects. Elevated plasma SLI levels are considered to be closely related to the severity of the diabetes. The ratios of SS-14 and SS-28 to the total amount of basal plasma SLI were analyzed using high pressure liquid chromatography (HPLC). The ratio of SS-14 to the total SLI was 71-80% in healthy subjects. The ratio of SS-28 to the total SLI increased from 26-30% in the diet group to 50-55% in the group on insulin. These findings suggest a possible pathophysiological role for gastrointestinal somatostatin in NIDDM.

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A 39-year-old woman who had been suffering from anorexia nervosa was found to have hypothyroidism. Serum T₄, free T₄, T₃, free T₃ and TSH were 3.19μg/dl, 0.5ng/dl, 15.3ng/dl, 1.2pg/ml and 162.1μU/ml, respectively. On careful questioning, she was found to have taken an iodine-rich diet. The serum iodine concentration was 122μg/dl (normal: 4-9μg/dl) and urinary iodide excretion was 13.05mg/day (normal: less than 2mg). After withdrawal of the iodine-rich diet, her serum T₄ gradually increased and TSH-returned to the normal range. She was diagnosed as having iodide-induced hypothyroidism. However, no significant elevation of serum T₃ or free T₃ was observed. Serum T₄, free T₄, T₃, free T₃ and TSH were 7.85μg/dl, 0.8ng/dl, 13.6ng/dl, 4.3pg/ml and 6.02μU/ml, respectively. The iodide-perchlorate discharge test result was negative. These findings suggest that there exists some unknown mechanism by which a patient with anorexia nervosa may be sensitive to excess iodide. Furthermore, it is of interest to note that in a recovery phase from the hypothyroid state, normalization of serum T₄ rather than T₃ is wellcorrelated to TSH secretion.

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The case of a 60-year-old woman with pheochromocytoma and concomitant adrenocortical adenoma in the same gland is presented. She complained of episodic headache, palpitation, nausea, vomiting and sweating. Physical examination revealed that the patient has generalized obesity, wet skin and paroxysmal hypertension, but no signs of Cushing's syndrome. Elevated levels of urinary noradrenaline, adrenaline and total metanephrine were sequentially observed. In addition, urinary 17-OHCS was also slightly elevated, but plasma cortisol was normal and suppressed after oral administration of 0.5mg of dexamethasone. Abdominal echography and CT scanning demonstrated a left adrenal tumor, which took up both ¹³¹I-meta-iodobenzylguanidine and ⁷⁵Sescintadoren in the same region. A left adrenalectomy was performed and the tumor was found to consist of two parts, pheochromocytoma (2.5×2.5×2.5cm) and cortical adenoma (2.5×3×5cm). A total of 23 reported cases showing evidence of hyperfunction of the adrenal cortex and the medulla were noted. So far as we know, this patient was the second case of pheochromocytoma with adrenocortical adenoma in Japan.

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Prostaglandin E2 (PGE2), thromboxane B2 (TXB2; as a stable metabolite of TXA2), prostaglandin F2α(PGF2α) and 6-keto-PGF1α(as a stable end product of prostacyclin) have been measured by using specific radioimmunoassay in the plasma of the cord artery immediately after delivery before the cord was clamped. Plasma prostanoid concentrations in normal deliveries (n=8, as controls) were 24.8±2.6 (PGE2), 246.8±37.0 (TXB2), 122.2±13.3 (PGF2α) and 82.1±7.7 (6-keto-PGF1α) respectively (pg/ml, mean±s.e). On the other hand, in fetal distressed deliveries showing continuous bradycardia (n=6), they increased significantly to 275.4±20.1 (PGE2), 948.6±102.5 (TXB2), 218.0±21.4 (PGF2α) and 1498.6±298.4 (6-keto-PGF1α) respectively (pg/ml, mean±s. e, p<0.005). However, both PGF2α/PGE2 and TXB2/6-keto-PGF1α ratios declined significantly from 4.70±0.33 to 0.68±0.05 and from 3.07±0.37 to 0.68±0.12 respectively (mean±s. e, p<0.005) in the fetal distressed group compared with those of the controls. From these results, it may be concluded that the cord artery, which is known as the patent source for the production of PGE2 and prostacyclin, did exert a sufficiently strong reaction to overcome the undesirable haemodynamic changes to maintain the fetal well-being in utero.

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The changes in tthe characteristics of thyrotropin (TSH) binding to thyroid plasma membranes during the activation of cyclic AMP-dependent protein kinase in the membranes were studied. Preincubation of thyroid plasma membranes with TSH or cyclic AMP reduced the maximal binding capacity but increased the association rate for TSH binding. In double reciprocal analysis, a marked reduction of the total number of binding sites and association constant was observed in the membranes treated with cyclic AMP. These reductions were also observed in the membranes preincubated with buffer alone. The degreee of these reductions, however, was greater in the membranes pretreated with cyclic AMP. During incubation of the membranes with buffer alone, cyclic AMP formation (activation of adenylate cyclase) was observed though the degree of the formation was lower than that induced by TSH.
The results sugggested that not only TSH receptor release from thyroid plasma membrane but also the modification of TSH binding activity in the membrane is produced by cyclic AMP-dependent protein kinase.

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The serum bone Gla-protein (BGP) and urinary γ-carboxyglutamic acid (γ-Gla) levels were determined in patients with primary hyperparathyroidism (PHP).
The mean serum BGP and urinary γ-Gla levels were 18.6±2.34 ng/ml and 65.5±4.62nmoles/mgCr, respectively, for the 11 patients with the skeletal type of PHP, 5.13±0.85ng/ml and 45.2±1.33nmoles/mgCr for the 4 with the chemical type, and 7.91±2.43ng/ml and 43.2±3.47nmoles/mgCr for the 5 with the renal type. Thus, patients with skeletal-type PHP had significantly higher serum BGP and urinary γ-Gla levels than those with the other type of PHP.
Serum BGP levels had significant positive correlations with serum Ca (r=0.64, P<0.005), serum Al-p (r=0.77, P<0.001) and serum PTH (r=0.45, P<0.005).
Urinary γ-Gla levels also had significant positive correlations with serum Ca (r=0.50, P<0.05), serum Al-p (r=0.67, P<0.005), serum 1, 25 (OH) ₂D (r=0.62, P<0.02), and serum BGP (r=0.72, P<0.001).
Mineral content in the left radius had significant negative correlations with serum BGP levels (r=-0.73, P<0.001) and urinary γ-Gla levels (r=-0.59, P<0.01).
As these data show, serum BGP and urinary γ-Gla levels clearly reflect the abnormal bone metabolism and can therefore be useful biochemical markers in PHP.

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CRF and vasopressin concentrations in major brain regions after bilateral adrenalectomy and their involvement in adrenalectomy-induced ACTH secretion were investigated. At 5, 14 and 28 days after bilateral adrenalectomy, the plasma ACTH level was greatly elevated, whereas hypothalamic CRF content was reduced at 5 days and was not changed at 14 and 28 days after adrenalectomy. The CRF concentration in the medulla oblongata was reduced at 2-4 weeks after adrenalectomy. On the other hand, the arginine vasopressin (AVP) concentration was significantly elevated 2-4 weeks after adrenalectomy. An intrajugular administration of anti-ovine or anti-rat CRF serum significantly suppressed the elevated plasma ACTH level in adrenalectomized, freely moving rats, whereas anti-AVP serum or antipressor AVP antagonist, dpTyr (Me) AVP did not suppress the ACTH level. These results indicate that CRF played an important role in the adrenalectomy-induced ACTH elevation but that vasopressin was not involved.

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The endocrine function of rat gonads with an experimentally reduced number of germ cells was examined to analyse the effect of germ cells on the surrounding somatic endocrine cells. Pregnant Wistar rats received a single i. v. injection of 10mg/kg B.W. of Busulphan on day 15 of gestation to prevent fetal primordial germ cells from starting mitotic division.
The gonadal growth and the number of germ cells in Busulphan-treated rats (B-rats) were severely arrested. Almost a normal testicular structure was formed in the males, while few follicular structures were formed in the females, suggesting that the presence of oocytes in the fetal ovary is a prerequisite to the formation of the follicle. The meiotic division of spematogonia in B-rats, which started on day 20 as in controls, stopped before the completion of spermatogenesis, and germ cells disappeared by day 50. The remaining germ cells and the associated follicles in female B-rats also disappeared by day 60 after repeating irregular estrous cycles for approximately 1month. Thereafter the ovary consisted of fibroblasts and morphologically interstitial-like cells.
Vaginal opening occurred in B-rats on day 28-30, a-week earlier than in controls. Changes in serum GTH after ovariectomy and the estradiol treatment suggested the maturation of the negative feedback sensitivity to estradiol in this period, and besides, earlier estradiol production with less dependency on gonadotropin. The vaginal epithelium of B-rats was cornified continuously after day 60. The ovarian cells in this period did not luteinize either morphologically or functionally in response to an ovulatory dose of hCG. During the same period, the conversion rate from progestestrone to estradiol in ovarian homogenates of B-rats was considerably higher than those of controls at any stage of the estrous cycle. High content of estradiol was detected in the testes of B-rats at any age. In male B-rats, both LH and FSH levels in serum were higher than controls. The serum testosterone concentration in B-rats was lower than the normal, while the testicular testosterone content was greater.
In conclusion, with a decreased number of germ cells, the rat gonads of both sexes secrete estradiol very efficiently.

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A 28 year-old woman was admitted to Jichi Medical School Hospital because of amenorrhea, cold intolerance, easy fatigability and body weight loss. She was pregnant at the age of 26 years. She delivered a 3230 g healthy girl at full term without any complications. However, she did not have any lactation or recurrence of menstruation after the delivery. Serum cortisol was 0.7μg/dl, and plasma adrenocorticotropic hormone (ACTH) was less than 10pg/ml. Both hormones failed to increase in response to insulin-induced hypoglycemia or exogenous arginine vasopressin. However, serum cortisol and urinary excretion of 17-hydroxycorticosteroids (17-OHCS) were significantly increased by the repeated administration of ACTH. Serum prolactin was 2.2ng/ml and the level did not rise after the administration of thyrotropin releasing hormone (TRH). Responses of release of adenohypophysial hormones including gonadotropins, growth hormone and thyroid stimulating hormone (TSH) were normal. Serological studies showed an antibody to the pituitary gland which was demonstrated by an indirect immunofluorescence technique. Plain skull X-ray film and brain computerized tomography revealed an empty sella of the normal size. These results indicate the presence of partial deficiency of ACTH and prolactin, and that autoimmune disorders may be involved in the pathogenesis of her hypopituitarism.

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In order to investigate the relation of weight loss and intravenous hyperalimentation therapy to low T₃ syndrome, serum T₃, T₄. rT₃ and TBG were determined by radioimmunoassay in 105 cancer patients.
The cancer patients were classified into 3 groups, Group I, II and III depending on the grade of weight loss, ranging up to a 5% change in weight loss from a healthy condition, from 5 to 9%, and more than 10%, respectively. Cancer patients under age 59 showed no significant difference in serum T₃, T₄, rT₃ and TBG among these 3 groups. However serum T₃ and T₃/T₄ in cancer patients at age 60 and over were significantly reduced in group III, compared to groups I and II. Serum rT₃ values were significantly elevated in group III of elderly cancer patients. The incidence of low T₃ syndrome in group III of elderly cancer patients was also significantly higher than in groups I and II.
In three out of 5 cancer patients with low T₃ syndrome, serum T₃ values increased after the intravenous hyperalimentation therapy, whereas no significant change in serum T₃ values was observed in two patients who died within one day after the final examination.
It is concluded that weight loss produced different effects on peripheral conversion of T₄ to T₃ between cancer patients under age 59 and over age 60 and glucose plays an important role in the pathogenesis of low T₃ syndrome except cases with very poor prognosis.

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