Changes in the electrical activity of the limbic-hypothalamic neural pathways during the process of adaptation to the immobilization stress were studied in the rabbit with chronically implanted electrodes. Both the hippocampally and the amygdaloidly evoked potentials in the medial basal tuberal region revealed decreases in their amplitudes during exposure to the 1st immobilization stress. Following the repeated exposure to the stress, the resting levels of their amplitudes decreased, and thus the decrease of amplitude in response to immobilization stress was reduced. To administered exogenous ACTH or cortisol acetate, those evoked potentials were significantly sensitive, and in the rabbit having been exposed to the repeated immobilization stress, the response to exogenous ACTH was observed to be altered.
It was considered that the limbic-hypothalamic neural pathways played a role in the establishment of adaptation mechanism by changing their responsiveness to the stressful stimuli and to ACTH and/or adrenal corticoid during the repeated exoposure to stress.

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Radioimmunoassays for rat FSH and LH have been studied taking advantage of rat FSH and LH radioimmunoassay kits supplied by the NIAMD. Separation of free and antibody bound labeled hormone was accomplished by the double antibody method with pre-precipitation technique. Although rat GH and prolactin did not react in the FSH assay, LH crossreacted slightly to a negligible extent. Hypophysectomized rat serum inhibited the reaction between labeled rat FSH and anti-rat FSH serum. To eliminate the nonspecific interference by serum, hypophysectomized rat serum was added to the diluent for reference preparations in the FSH assay. Rat GH and prolactin did not react in the LH assay. However, FSH crossreacted in the LH assay to a greater degree than LH in the FSH assay. This indicates that LH concentrations may be overestimated when samples with extraordinary large amounts of FSH are measured. Hypophysectomized rat serum did not influence the LH assay. The FSH activity of pituitary extracts determined by bioassay and that by radioimmunoassay agreed well. And there was also a good correlation between LH values obtained both by bioassay and by radioimmunoassay. Although a marked decrease in pituitary FSH and LH levels was found between proestrus and estrus, serum FSH and LH levels were elevated only slightly at 2:00 PM of the proestrus day. Serum and pituitary FSH and LH levels increased after ovariectomy.

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Arginase activity in the kidney and the prostate of rats was found in both supernatant and precipitate after centrifugation at 12, 000×g for 20min. Ratios of enzyme activity in supernatant to precipitate varied in tissues examined; ratios of the liver and the ventral prostate were 5.5 and 2.3, respectively, however that of the kidney was 0.3. Arginase in the precipitate seems to be attached to membraneous element, because the activities of arginase are lost from nucleus after Triton X-100 treatment or heavy sucrose purification.
Arginases from supernatant and precipitate in kidney and ventral prostate showed similar Km for substrate, but the rate of activation by Mn⁺⁺ was slightly higher in supernatant than in precipitate.
Castration caused a marked decrease of arginase activity in the precipitate of ventral prostate, while the change of the activity in supernatant was quite moderate. On the other hand, no significant changes of enzyme activity were observed in both supernatant and precipitate of the kidney. Testosterone treatment on castrated rats evoked an increase of the enzyme activity in the precipitate of kidney and of ventral prostate, and the elevation of the arginase activity in the supernatant was followed by the increase of the activity in the precipitate. The increase in the enzyme activity of ventral prostate was more prompt than in kidney after testosterone administration.

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As a general secretion pattern of gestagen during the functional luteal phase inthe rat, the level of progesterone is always high and that of 20α-hydroxypregn-4-en-3-one (20α-OHP) is low. Thus, the reciprocal relationship is generally observed between two steroids. In the midpregnancy corresponding to the time of placentation, however, the characteristic pattern of gestagen secretion was observed as an exception, i. e. in parallel with progesterone, the level of 20α-OHP also rises.
Hypophysectomy performed at 12 day of pregnancy, did not alter this characteristic secretory pattern. The luteotrophic factor which resulted in parallel rise of progesterone and 20α-OHP at this stage, therefore, was not seem to be the pituitary origin. Hysterectomy in addition to hypophysectomy, caused significant decrease of both steroids and nullified the parallel rise. The luteotrophic factor seemed to be secreted from pregnant uteri. Pregnant uteri from which fetuses alone were removed, however, could not produce the parallel rising of two steroids, though the secretion was continued in some extent and showed almost the same level with that of pseudopregnant rats bearing deciduomata.
The fetuses are considered to be essential to form the endocrine milieu which bring about the characteristic pattern of gestagen secretion at midpregnancy, and this luteotrophic factor might be produced and secreted as the results of an interaction between placentae and fetuses.

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KK mice, which proved to be of chemical diabetes when kept on usual laboratory chow, developed hyperglycemia with hypertrophy of epididymal adipose tissue when fed a semisynthetic diet. Effects of the semisynthetic diet on metabolic activities were investigated in vitro. In adipose tissue, lipogenesis from acetate was markedly activated, but either oxidation of glucose or lipogenesis from glucose was hardly activated. Insulin sensitivity of the tissue was diminished in glucose oxidation, but not in lipogenesis from acetate. Hepatic lipogenesis from both glucose and acetate was markedly stimulated. Thus, activation of hepatic and extrahepatic lipogenesis, and reduction of insulin sensitivity in peripheral glucose metabolism may result in the onset of overt diabetes associated with adiposity.
These metabolic profiles were similar to those of genetically obese KK mice, yellow KK. A possible mechanism of the diabetogenic action of the diet is discussed on the basis of the metabolic defects of KK strain.

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In order to elucidate the importance of the biological role of placental mammotropic hormones in the mammary development during pregnancy, the correlations between the number and weight of placentae and some indices of mammary development were examined using nulliparous C3H/He pregnant mice. On day 8 of pregnancy, the number of placentae was adjusted to 1-12 each by removing surgically the placentae with fetuses and all the mice were killed on day 19 of pregnancy. DNA and RNA contents and RNA/DNA ratio in bilateral inguinal mammary glands and lobuloalveolar rating of the right third thoracic gland were employed as the indices of mammary development. Positive and statistically highly significant correlations were obtained between both the number and weight of placentae and each index of mammary development, and the number and weight of placentae had higher correlationswith RNA and RNA/DNA than with DNA. On the other hand, pituitary levels of prolactin and growth hormone had no correlations with any index of mammary development. These results provide evidence that placental mammotropic hormones contribute quantitatively to the mammary development during pregnancy in mice and suggest that the lactogenic effect of placental mammotropic hormones would be more prominent than their mammogenic effect at late pregnancy.

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The hypotriglycedemic action of ACTH was investigated in the hyperlipemic patients of various diseases. This effect was apparent within 30 min after intravenous injection of the hormone and lasted up to 96 hr when it was administered intramuscularly. ACTH had no effect on the serum cholesterol or phospholipid concentration. As possible causes of this effect of ACTH, fatty acids mobilization and lipoprotein lipase activation were excluded and hepatic involvement was suggested.

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A double isotope derivative method for urinary aldosterone determination was improved in terms of economy (to one fifth the original cost) and efficiency (to less than half the time) by a combination of several individual improvements.
Aldosterone-4-¹⁴C was used as an indicator, eliminating the procedure of preparing aldosterone-¹⁴C-diacetate. ³H-acetylation was done after, instead of before, dichloromethane extraction and a thin layer-chromatography, to avoid unnecessary acetylation of abundant contaminants. The cost of radioisotope was thus reduced to one tenth. dl-Aldosterone diacetate, added as a carrier, was easily located on thin layers by ultraviolet light. Two dimensional thin layer, instead of repeating one dimensional paper chromatography, was employed for the purification, thereby shortening the time to one twentieth to thirtieth, and enabling to eliminate the exidation of the diacetate to the monoacetate. The specific radioactivity of 3H-acetic anhydride was determined by acetylation of dlaldosterone mixed with urine, instead of cortisone or dl-aldosterone, for both economy and calibration. One technician can thus work out with 4-8 samples a week.
Aldosterone excretion in 24 hr, thus determined, was 10.99±3.83 (S.D.)μg for normal subjects and 32.12±8.38μg for preoperative primary aldosteronism with a postoperative decrease to 12.03±4.10μg.

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By the use of isolated bovine thyroid cells (ITC), accumulation of T₄ in thyroid tissue has been studied. ITC were chosen to disclose this thyroid cell function per se by eliminating the effect of follicular structure and contaminated serum. Cell/medium ratio (C/M) of 125I-T₄, used as an indicator of T₄ accumulation, was 17.7 when ITC were incubated in Eagle's solution. On the other hand, the ratio in the thyroid slice and erythrocytes was 1.1 and 3.0 respectively. By equilibration chamber method, T₄ accumulated more in ITC than in erythrocytes. The observed accumulation of T₄ in ITC was reversible when re-incubated with normal human serum. Displacement of ₁₂₅I-T₄ by non-labelled T₄ was not observed at the range of added T₄ from 10 to 1000 ital. Essentially the same result were obtained when the liver, thyroid slice or erythrocytes were studied. Therefore, the number of T₄-binding sites appears to be very large. Increased deiodination of ¹²⁵I-T₄ was observed when ¹²⁵I-T₄ was incubated with ITC, whereas conversion of ¹²⁵I-T₄ to ¹²⁵I-T₃ was not remarkable. It is concluded that ITC obviously concentrate T₄ by an entirely different mechanism from that in serum TBP.

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A study was carried out to observe the influence of enucleation on the excretion of a gonadotropin-inhibiting substance in male rats. No significant difference in the inhibitory effect on the ovulation induced with PMS and HCG was observed between the urinary extracts of the intact and blinded rats. The observations suggest that effect of blindness on the secretion of a gonadotropin-inhibitor was different from that on melatonin formation, which is known to be increased by blindness, in the rat pineal.

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