The authors, in order to perform the analysis of luteal functions, measured progesterone (called P. hereafter) and pregn-4-ene-20α-ol-3-one(called 20-OH-P. hereafter) in the ovarian venous blood of rats, in the various stages of reproductive cycle. The ovarian venous blood 3-7 ml was collected for 2-4 hours by a cannula fitted to a branch of the ovarian veins and was extracted by a modified method of SHORT'S, and was developed on paper-chromatography (Heptane-Formamide), then the absorptions of UV (240 mμ) of each portion of the paper were sought and plotted for densitogram, and by pranimetry of the areas occupied by each of the peaks, P. and 20-OH-P. were calculated and quantitatively analyzed.
(1) P. during normal estrus temporarily increases in the afternoon of proestrus when the ovulating hormone is released from hypophysis, its concentration reaches approx. 110 μg/100 ml blood which is equivalent to about 1/3 of that of the second half period of gestation, then somewhat increases in early, diestrus when the corpus luteum develops most. 20-OH-P. is found throughout the estrous cycle, and its maximum value is approx. 240 μg/100 ml blood. That is to say, the ovary of rats secretes P. even during the normal estrous cycle, but the secretion does not last long.
(2) P. during gestation is already high on its 4th day and raises to the maximum value of the 15th day, but it is markedly low immediately before and after the parturition. On the other hand, 20-OH-P. showes rather lower value in the first half period of gestation than in normal estrous cycle, but it reaches appox. 260 μg/100 ml blood on the 15th day. This high concentration is found once more immediately after the parturition. The picture of 20-OH-P. showes a characteristic difference from that of P., although it has been reported there was a parallel relationship between P. and 20-OH-P.
(3) P. on the 8th day of lactation is secreted in quite a high concentration, and by the fact that P. of the rat having 6 sucklings is higher than that of the rat haviug 2 sucklings in concentration, it is demonstrated that the secretion is evidently affected by the strength of suckling stimulation. With regard to 20-OH-P., the concentration is low and no difference is observed as in the case of P.
(4) The ovary of rats hypophysectomized and bearing pituitary graft undeneath renal cupsule, secretes a large amount of P., but a little of 20-OH-P.

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To investigate the androgen-biogenesis of rat testis in vivo, a new efficient method for administration of the precursor, named "Inratesticular Infusion Method" (abbr. ITI), was devised (Fig. 1). Compared to the intravenous injection of the precursor1), this was much useful for tracing of the intermediates and for investigation of the action mechanism of gonadotrophin. In this report, progesterone-4-C¹⁴ was given to eviscerated adult rats by ITI (1 μc=0.1 ml/hr. for 1 hr.), and the effects of HCG and hypophysectomy on the androgen-biogenesis were studied. Eight radioactive steroids including unidentified ones were detected in the infused testis, and their concentrations are given in Table 1. Since the main pathway from progesterone to testosterone, i. e. ce-hydroxyprogesterone (17-OHP) → androstenedione testosterone, has already been established by in vitro experiments4-6), the concentrations of only these member steroids were questioned for the discussion (Figs. 2 & 3).
(1) Effect of hypophysectomy : The steps later than progesterone in the testosterone-biogenesis system (abbr. TGS) seems to be impared almost evenly by hypophysectomy, although a slight tendency of relative accumulation of androstenedione is observed in the course of regression. Series of HCG(S) groups (Fig. 2, lower row) might indicate a picture of regression in the maximum capacity of the functioning TGS after hypophysectomy. At the 10 post-operative day, the most of TGS is impared and its immediate responsiveness to HCG is mostly abolished. This impared TGS, however, can be restored by a long period administration of HCG and again produces testosterone.
(2) Effect of RUG: Single injection of HCG to either normal or partial impared TGS, increases concentrations of 17-OHP and testosterone strikingly, but not that of androstenedione. As was already pointed out in our previous reports1, 7), the increased concentration of testosterone in the testis was regarded as the outcome of the increased synthesis accompanying with the secretion, but not a mere accumulation due to suppression of its release. In this point of view, the following deduction might be drown from Fig. 2 : a) HCG action is related even to the process later than progesterone, and it accelerates the steps of both progesterone→17-OHP and androstenedione→testosterone; b) The step between 17-OHP and androstenedione is little influenced by HCG, and also this seems much slower phase than the steps progestrone→17OHP and androstenedione → testosterone. Thus the concentration of androstenedione might be low and not changed by HCG stimulation. (3) In the shorter infusion experiments, as shown in Fig. 3, a picture of presumed ealier conversion, i. e. relative high concentrations of the intermediates, is seen. Furthermore, the accelerated steps of TGS by HCG are well indicated in comparison between the cases treated with and without HCG (Fig. 3., ITI. O. 5 hr.).

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Twenty four heifers of Holstein in 3 stations were administered with synthetic estrogen "Euvestin", one million I. U. in total, and their induced lactation, reproduction and growth were examined.
The total milk yeild was 952.5 kg., thepeak yield 5.60 kg., and milk fat 3.35% in average. There we-re differences inresults between stations, and it suggested that not only genetic factors but also environ-mental factors played an important role.
The coefficients of correlation between dairy characters were calculated and the phenotypic resemblance between half sibs in dairy characters showed fairly high value, O.318-0.588.
The influence of the treatment upon reproduction was not so much excepting few cases, and that upon growth was slight.

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[in Japanese]

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[in Japanese]

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Since, it was difficult to understand that the sensitivity of the rat for inducing ovulation by the single subcutaneous injection of HCG is about equal to that of the rabbit in Friedman's test, the effect of route of administration on induced ovulation in adult rats was studied.
An improved method for intravenous injection of adult rats is devised to eliminate the inhibitory effect of anesthetization on the induction of ovulation⁴⁾. The injection is performed safely under unane-sthetized condition without fastening the animal. The rat is took up gently from its back by a hand of the assistant. The head and one of forelimbs of the rat are held by the ring formed by the thumb and the forefinger and the other forelimb is held between the fore-and middlefingers of the hand. The animal is stood on its rump in the other palm of the assistant and the legs and the tail are held by fingers of the hand. The one side leg is held by the thumb and the forefinger. The vena metatarsea dorsalis pedis may be elevated by applying pressure to the saphenous vein by the ball of the forefinger or the tip of the thumb. The paw is held by the left hand of the operator and the hormone is injected into the metatarsal vein by 1/4 or 1/5 needle for blood vessel. This technique is also applied to obtain the blood.
The response of rats to induce ovulation by the subcutaneous injection of HCG or the combined pre-paration of 9 parts of HCG and 1 part of pituitary powder was slightly less sensitive than Friedman's test. By the intraperitoneal injection, The ovulating response by HCG was 3 time sensitive than the cases by subcutaneous injection. The most sensitive route to induce ovulation by HCG or by the com-bined preparation was the intravenous injection, which was 7 or more times as sensitive as the subc-utaneous injection and about 2 or 5 times as sensitive as the intraperitoneal administration or Friedman's test respectively. These results may furnish some information for clinical application of gonadotrophins. In the test of induced ovulation in rats, the animals are autopsied in the afternoon of the day of vag-inal proestrus, when the uterus is distended with fluid in intact animals. However, in ovulation induced animals, it was observed a tendency to decrease the uterine weight and uterine fluid.

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