The adrenocorticotrophic effect of a synthetic substituted adrenocorticortophic hormone (ACTH), α^1-18NH₂-D-Ser¹-Lys^{17, 18}-ACTH (CIBA 41, 795-Ba) has been compared with that of α^1-24-ACTH (tetracosactide), α^1-24-ACTH depot (tetracosactide depot) and α^1-18NH₂-Gly¹-ACTH (giractide) in the rabbit. Plasma corticosteroid levels after saline injection were higher in the afternoon than in the morning. The highest value was observed at 3 p.m. 41, 795-Ba, either given intravenously or intramuscularly, was shown to be the most potent peptide followed by tetracosactide depot and was 15 times more potent than tetracosactide and giractide in steroidogenic activity in the rabbit The intravenous administration of 41, 795-Ba caused more sustained stimulation of the adrenal cortex than the intramuscular injection. These results reveal the diurnal variation pattern of the pituitary-adrenal axis of the rabbit similar to that of the rat and also confirm the finding that α^1-18NH₂-D-Ser¹-Lys^{17, 18}-ACTH is a potent adrenocorticotrophic peptide without the addition of any agent to delay its absorption in the rabbit.

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Effects of norethisterone (NT) purified norethisterone (pure NT), norethynodrel (NE), medroxyprogesterone acetate (MAP), chlormadinone acetate (CMA) and desoxycorticosterone acetate (DOCA) on serum and liver lipid levels and serum lipoproteins were examined in both intact and estradiol-treated male rats.
NT and NE caused a decrease in serum cholesterol and phospholipid levels, an increase in liver cholesterol level, no significant change in triglyceride levels of both serum and liver, with a significant change in serum lipoprotein patterns; a decrease in α-and β-lipoproteins and a marked increase in pre β-lipoprotein. Pure NT decreased serum cholesterol without causing any change in lipoprotein pattern. MAP, CMA and DOCA caused almost no effect on lipid levels in serum and liver, but CMA and DOCA increased α-lipoprotein and decreased β-and pre β-lipoproteins. An acute treatment with estradiol caused a decrease in α-and β-lipoproteins and an increase in pre β-lipoprotein with a decrease in serum lipid levels and an increase in liver lipids. By contrary, a chronic treatment with estradiol caused an increase in α-lipoprotein and a decrease in β-lipoprotein with a marked hypercholesterolemia. This increase of α-lipoprotein in estradiol-treated rats was prevented by NT and NE, not affected or rather decreased by MAP but further increased with CMA and DOCA.
These data suggest that the effects of synthetic progestational steroids on lipids are classified into two groups, 19-nortestosterone derivatives and 17a-hydroxyprogesterone derivatives including DOCA. The former caused a decrease in serum lipid levels with an increase of pre β-lipoprotein and a decrease of α-lipoprotein. The latter caused almost no change or a slight increase in serum lipid levels with a decrease in pre β-lipoprotein and an increase in α-lipoprotein, though it was not found in MAP.

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Biological activity of porcine calcitonin was most actively inactivated by the rat kidney homogenate than by other tissue homogenates. Among the various subcellular fractions of the rat kidney homogenate examined, microsome fraction was most active in the in vitro inactivation of porcine calcitonin. Inactivation of porcine calcitonin by the rat kidney microsome was dependent on pH and temperature. Inactivating activity of the rat kidney microsome was inhibited by 1×10^-3M monoiodoacetate and 1×10^-5M p-chloromercuribenzoate. These results suggest that porcine calcitonin is probably inactivated by a SH-enzyme in the rat kidney microsome. However, the participation of other enzymes cannot be ruled out, since the inactivating activity of the rat kidney microsome fraction is also inhibited by 1×10^-4M diisopropylfluorophosphate.

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Fifteen postmenopausal women were given 25mg, 50mg of clomiphene citrate daily by mouth for 3 consecutive days. Significant (p<0.01) decrease of serum LH (73%, 65%) and FSH (76%, 76%) resulted after administration of 25mg and 50mg clomiphene citrate respectively. The suppressive effect was sustained for at least 4 days after cessation of this drug.
On the other hand decreased LH and FSH levels after administration of ethinyl estradiol increased again by simultaneous administration of clomiphene citrate. These results suggest that estrogenic effects of clomiphene citrate are observed in untreated estrogen deficient subjects but anti-estrogenic effects are evident when serum estrogen levels are restored in subjects with estrogen deficiency.

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Human chorionic tissues were cultivated in vitro in the presence of ³H-proline in order to study the synthesis of hCG and its subunits by the placenta. After terminating the culture, tissue extracts and media were individually gel-filtrated on Sephadex G-100. The eluted fractions were radioimmunoassayed for hCG, hCGα and hCGβ and were measured for ³H-radioactivity. Label incorporation was determined by immunoprecipitation. Elution profiles of tissue extracts showed the existence of large immunologic forms of hCG, hCGα and hCGβ emerging near the void volume. The amounts of these large immunologic species in chorionic tissue gradually decreased during the course of cultivation. ³H-proline was almost exclusively incorporated into the large immunologic forms of hCG, hCGα and hCGβ within the chorionic tissue during the 5-hour exposure. A great quantity of hCGα was found in the media after the 3-day culture, while the amount of hCGβ found in the media was minute. After a 15-minute pulse, the ³H-radioactivity peak within the chorionic tissue appeared in tha void volume, coincidental with hCG immunoreactivity. During the chase period, there was a shift of the ³H-radioactivity peak associated with hCG immunoreactivity from the void volume to the more retarded area. In the media until after the 60-minute chase, no labeled hCG and its subunits appeared. Within the media after the 3-hour chase, the hCG peak associated with ³H-radioactivity was more retarded on Sephadex G-100 than that within the tissue extract after the 15-minute pulse. These results suggest that the large immunologic forms of hCG, hCGα and hCGβ are synthesized as the earliest detectable biosynthetic forms and that they may then be converted to small molecule species.
In the culture of molar trophoblastic tissues after a 15-minute pulse, considerable amounts of hCG and its subunits accompanied by high ³H-radioactivity had already been secreted into the media. These observations suggest that protein synthesis by molar trophoblastic tissue is markedly enhanced as compared with that by normal chorionic tissue and that immunoreactive materials synthesized in molar trophoblastic tissue may be secreted more readily than those synthesized in normal chorionic tissue.

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Concurrent observations were made in the rat on the changes in the milk production, body and organ weight, food and water consumptions and in the ovarian function in two separate series of experiments in which the period of lactation was prolonged to 60 and 45 days, respectively, by replacing suckling pups by younger ones.
In most of the variables examined, marked changes occurred between day 20 and 30 of lactation, that is, at the stage corresponding to the end of the normal lactation period. Milk production rate during prolonged lactation expressed by daily gain in weight of litters decreased to 60% of the level before day 20, and was associated with a great reduction of nucleic acid contents of the mammary gland. Definite decreases in weights of the anterior pituitary and the adrenal glands were observed. The food intake remained constant from day 15 of lactation onwards, therefore, the feed efficiency for milk production declined gradually during the period of normal lactation remaining at a low level thereafter. After the first recurrence of vaginal estrus which also occurred between day 20 and 30, the replacement of litters was followed by the appearance of estrus, whereas replacement before day 15 did not affect the ovarian function. In addition to these changes, a depressing effect of estrus on the milk production was observed.

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The duration of the diestrous period in vaginal smears and the levels of progestins in ovarian venous blood were investigated in rats whose lactation period was prolonged by replacing pups at appropriate intervals.
In prolonged lactating rats, the first diestrous period after the postpartum ovulation (21.7±0.8days) was similar to that occurring in normal lactating rats. Subsequently proestrous or estrous vaginal smears reappeared at intervals during prolonged lactation. A total of 19 rats were studied during this period of prolonged lactation and 44 diestrous periods were observed. Forty-eight % of these periods ranged in length from 11 to 16days (mean of 12.7). Very short diestrous periods lasting less than 3 days were observed 25% of the time. Diestrous periods lasting more than 17days were observed only infrequently (7%).
Progesterone concentration in the ovarian vein during the 2nd diestrous period reached a peak 4days after the 1st estrus and the level was maintained until 11 days after the 1st estrus. The level of 20α-hydroxypregn-4-en-3-one remained fairly constant throughout the 2nd diestrous period.

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Intratesticular tissue fluid (ITF) was obtained by centrifugation of the decapsulated testis of the adult rat. Testosterone level in ITF was increased by direct injection of LH into the testis and was lowered by anti-LH serum. Based on the result of previous reports with testosterone in testicular vein blood, a simplification of the LH bioassay without imparing sensitivity and accuracy was undertaken using ITF as the material for testosterone measurement. Dose-response relationship between injected LH and testosterone concentration in ITF was observed. The sensitivity of the assay was 5 ng for LH (NIH-LH-S15). FSH (NIH-FSH-S10) and prolactin (NIH-P-S11) had no detectable activity on testosterone production. This assay method depending on biological activities of LH will be helpful for unbiased evaluation of the result obtained by radioimmunoassay.

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To examine the content and the composition of free amino acids in the intraluminal fluid of rat epididymis, the fluids were obtained by light pressure on the dissected tissues. The amount of the total free amino acids in the pressed fluid from the caput epididymis was significantly higher than those of the cauda epididymis and the testis. Glu and Gln were predominant amino acids in the caput, and their amounts occupied more than half of the total ninhydrin reactive compounds. Such a high concentration of Glu and Gln was not observed either in the cauda or in the testis. Castration decreased Glu and increased Gln in amount. Testosterone treatment to castrated animals did not restore Glu and Gln contents in the pressed fluid from the caput epididymis to the level observed in intact rats completely. Therefore, it was assumed that a large amount of Glu in the caput was due to many factors; secretion and metabolism of epithelial cells of the gland which might be regulated by androgen, inflow of rete testis fluid, and sperm metabolism of amino acids in the epididymis. The results obtained from the caput epididymis to which the efferent duct of the testis was ligated also supported this interpretation.

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To assess a possible postmortem change in the level of cyclic AMP, the thyroids were snap-frozen at various time intervals after removal. Rats were fed a low-iodine diet (LID) with PTU for 2 weeks and a week after PTU discontinuation (PTU withdrawal). In all cases, the cyclic AMP level tended to increase as time elapsed from removing till fixing the thyroids, but in the PTU withdrawal group, the level was rapidly increased 2-fold after 5 min. In an acute experiment, the thyroids were removed under anesthesia and frozen rapidly. Intravenous administration of ovine thyrotropin (250mU) and TRH (500ng) brought about a rapid increase in the thyroidal level of cyclic AMP to 40% to 20% over the control level. Two weeks after PTU treatment, circulating thyrotropin was increased to a maximum of 19-fold and a further enhancement (“rebound”) was observed after PTU withdrawal. PTU treatment led to an increase in the thyroidal level of cyclic AMP per μg DNA to 60% over the control value. Following PTU withdrawal, the rise in the level of cyclic AMP returned to the normal level. However, there was no change in the concentration when it was expressed as per mg wet tissue weight. Therefore, the increase in the thyroidal concentration of cyclic AMP per μg of DNA may be due to an increase in volume of the follicular cells.

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Effect of continuous illumination (LL) on ovarian functions was compared at various ages between the rats exposed to LL from 70 days of age (LL-70) and exposed to LL from the day of birth (LL-0). LL-0 rats retained corpora lutea in their ovaries in higher incidence than LL-70 rats.
Effect of reserpine on the restoration of cyclicity was studied in LL-0 and LL-70 rats shortly after they became persistent-estrous. LL-0 rats restored cyclicity in higher incidence than in LL-70 rats.

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A method for the estimation of the serum testosterone binding capacity (TeBC) using hydrophobic resin, Amberlite XAD-2, was developed. The serum was incubated with a saturating amount of testosterone-1, 2-³H at 15°C, unbound testosterone was adsorbed to the resin and the 3H-radioactivity remaining in the supernatant fluid was counted. Under these conditions, the normal levels and their standard deviations were 15.08±3.39ng/ml (n=7) for male and 35.06±3.56ng/ml (n=6) for female respectively. Precision of the method was 6.29%. TeBC in the third month of pregnancy was approxinately 1.5 times more than that of non-pregnant women, and approximately 3 to 5 times in the tenth month.

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Castrated Wistar male rats were primed with varying amounts of estradiol benzoate (EB) for successive 2 days and progesterone (P) on the third day 6-8hr prior to the behavioral test. The tests were performed 4 times at 2-3 weeks intervals. As a priming procedure for the first behavioral test, 50μg EB and 0.5mg P were given. The quantity of P was kept constant thereafter. For the second test, the dose of EB was increased to 100μg, but decreased again to 50μg and further to 10μg for the third and fourth tests, respectively. The incidence of animals showing lordosis was quite low, and was not significantly changed by increasing or decreasing the dosage of EB during the series of the behavioral tests. Forty-three out of 51 animals never showed lordosis at all 4 behavioral tests. In contrast, 5 out of 8 rats which responded to mountings by the males continued to display lordosis behavior throughout the series of the successive 4 tests. This consistence of individual responses during the series of the behavioral tests may indicate the possible existence of individual difference in lordosis response in male rats.

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The reaction of LATS activity with Staphylococcal Protein A, a specific binding protein with the Fc part of human IgG (1), IgG (2) and IgG (4), was examined. When IgG (1), IgG (2) and IgG (4) subclasses were removed from LATS positive sera or LATS-IgG fractions by affinity chromatography on Protein A-Sepharose, LATS activity decreased. Almost all LATS activity was found in the fraction that reacted with Protein A. It is suggested that LATS has an expression of a very distinct immunoglobulin G structure, and that LATS activity is distributed mainly in the fraction containing IgG (1), IgG (2) and IgG (4) in LATS positive serum.

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