The role of various hormones on the early stage of spermatocytogenesis in the newborn rats was investigated.
To eliminate the influence of anterior pituitary hormones in the early life either the testes of newborn rats were implanted into the testes of hypophysectomized adult rats, or the pituitary func-tions of newborn rats were suppressed by injection of estradiol or testosterone. Effects of FSH, ICSH or testosterone on these newborn testes were examined morphologically.
1) In the testes of newborn rat which were implanted into the testes of hypophysectomized adult rats, initiation of the spermatogenic process was not prevented even in the absence of pituitary hor-mones, and gonocytes were developed up to the pachytene spermatocytes. The seminiferous tubules of the implanted testes were stimulated slightly with testosterone. The further tubular development was achieved with FSH and the tubules containing spermatocytes were increased in number. In the testes of newborn rats which were implanted into the testes of intact adult rat, the tubular development was accelerated and supporting cells increased in number and size. It was noted that number of mature germinal cells up to pachytene spermatocytes was larger in the testes implanted at 6-day-old than in those implanted on the day of birth.
2) Injections of FSH and a high dose of PMSG resulted in development and maturation of the supporting cells. ICSH, testosterone and estradiol were not able to stimulate the supporting cells in newborn rats. However, the development and secretory function of supporting cells seemed to be stimulated by the action of FSH, either in cooperation with testosterone, or after priming with tes-tosterone.
3) The spermatocytogenesis were retarded markedly when pituitary function of newborn rats were suppressed by injection of estradiol.
However, the development of germinal cells in the testes of newborn rats treated with large dose of testosterone was not compared with that of intact newborn rats.
These results suggest that the development and secretory function of supporting cells in newborn rats might be controlled by the action of FSH, and that the delicate balance in the intratubular en-vironment which is essential for the formation of type A spermatogonia and primary spermatocytes. might be established by the action of FSH in cooperation with androgen.

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By the single injection of estradiol at 10 PM on the day of metestrus, or progesterone at 7 PM on the day of diestrus, ovulation in the next estrous cycle occurred 24 hr earlier in the adult 4-day cyclic mice under the light controlled condition (light on 5 AM and off 7 PM).
In some of the mice treated with estradiol, the 3-day cycle occurred 2 to 4 times successively and the rate of recurrence of the cycle was higher in the estradiol-treated group than in the progesterone-treated group.

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Histochemical demonstrations of Δ⁵-3β-hydroxysteroid dehydrogenases (OH-SDH) using DHA and pregnenolone as substrates and of 17β-0H-SDH using estradiol-17β and testosterone as substrates were carried out on ovarian and tubal hamster eggs at various developmental stages. To observe ovarian eggs, ovaries about 2 hrs. before ovulation were taken and cut at the thickness of 15 μ using a cryostat. Tubal eggs were collected as follows; at 2 hrs. after ovulation for unfertilized eggs, 4 hrs. for penetrated eggs, 32 hrs. for 2-celled eggs, 52 hrs. for 4-celled eggs, 65 hrs. for 8-celled eggs, and 76 hrs. for blastocysts. For the histochemical demonstration of enzymes, DICKMANN & DEY method was employed, the composition of medium being 1.8 mg of a substrate, 4.0 mg of NAD, 2.0 mg of Nitro-BT, and 10 ml of 0.1 M phosphate buffer solution (pH 7.5).
The results obtained are as follows.
While there was no Δ⁵-3β-OH-SDH and 17β-0H-SDH activities in the eggs from primordial, primary, secondary and Graafian follicles, strong activities of these enzymes appeared in unfertilized and penetrated eggs. In the eggs of the last two stages, blue diformazan granules produced by the enzyme reaction were spread evenly throughout the cytoplasm. The enzyme activities decreased in the eggs of 2 to 4-cell stages, but increased again in those of 8-cell stage. Throughout the stages, diformazan granules were located at perinuclear region and at periphery of the cytoplasm. In blastocysts, the activities of Δ⁵-3β-OH-SDH with DHA as substrate and 17β-OH-SDH with testosterone as substrate somewhat decreased, but other enzyme activities were retained: diformazan granules were spread throughout the cytoplasm of inner cells as well as trophoblasts.
The presence of strong OH-SDH activities in 8-celled eggs and blastocysts may be related to the cell-differentiation from blastomeres into inner cells and trophoblasts, while the significance of enzyme activities in unfertilized and penetrated eggs is unknown, since such activities have no relationship to fertilization.

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The data used in the present study were collected from the records in the Thoroughbred Year-lings Catalogue of Japan (from 1970 to 1973) which was published by the Japan Light-Breed HorseAssociation. The catalogue contained three breeds of horses, i.e., Thoroughbred, Non-Thoroughbred, and Thoroughbred Strain, and data collected from eight districts (see the remarks of Table 1). Thetotal number of offspring and of sires listed in the catalogues were 20, 662 and 493, respectively. The results obtained from a study on the secondary sex ratio of race horses in Japan are summarized as follows.
1. Total sex ratio was 49.3 ( ?? %). Its shift was significant at a 5% level. With regard to eachdistrict and each breed, a shift of sex ratio to female was seen only in the Thoroughbred breed in the C district. There was no significant shift of sex ratio in the total of the eight districts for any breed, or in the sum total of the three breeds for any district (Table 1).
2. A regional difference in sex ratio was observed most frequently between the H and any other district. It was difficult, however, to find a general rule for regional differences from the present study. Therefore, it cannot be concluded that there is a regional difference in the sex ratio of race horses (Table 2).
3. A large number of sires showed a shift of sex ratio to female than a shift to male (Table 3).
4. Shifts of sex ratio were found in the Thoroughbred breed in February and March, in the Non-Thoroughbred breed in March, in the Thorughbred Strain in February, and in all the three breeds in February and March. It cannot be concluded, however, that there is a relationship between season and sex ratio (Table 4).
5. Shifts of sex ratio were noted in sires at six years of age (to male), and at twelve and eigh-teen years of age (to female). When the sires were divided into three age groups, a significant dif-ference in sex ratio was found only between the two older groups. No permanent shift of sex ratio with the advance in age of sire, however, could be noted in the present study (Table 5 and 6).

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It has been demonstrated by IMAMICHI et al. (19571964) that follicle stimulating hormone (FSH) has more potent in inducing ovulation than luteinizing hormone, and also has luteinizing activity.
In this study, dairy cows with follicular cyst were treated by intravenous injection of highly purified FSH.
The results obtained were as follows.
1. Four cows treated with 10 Armour Units (A.U.) of FSH were not cured. Normal estrus oc-curred in 34 (81.0%) out of 42 cows injected with 20 A.U., and 10 (83.3%) out of 12 cows injected with 40 A.U. within 27.6 and 22.6 days, on the average, after the treatment, respectively.
The cystic follicles in the greater part of cows luteinized without rupture around 10 days after the treatment, but those in a part of cows either luteinized after rupture or disappeared by regression.
The number of cows conceived and the average days from the treatment to conception in cows injected with 20 and 40 A.U. were 32 (76.2%) of 42, 31.2 days and 9 (75.0%) of 12, 29.1 days, respec-tively.
As the group injected with 40 A.U. included cows with bilateral cystic ovaries or cows received previous GTH treatment more than the group injected with 20 A.U., so the reasons for interpreting that no significant differences were found in recovery rate between the doses of 20 and 40 A.U. might be depended on the ovarian conditions of the cow.
2. These results indicated that FSH could induce ovulation and luteinization in cows with fol-licular cysts, and its therapeutic dose might be 2040 A.U. [300600 rat ovulating units (S.C.)] when injected intravenously. In addition, the authors stress through this experiment that the effective dose of FSH for cystic ovary was smaller than that has been generally used for ovarian quiescence in large animals (50 A.U.).

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Fertility with artifical insemination using frozen semen was pursued in four bitches.
The semen was collected from 3 adult males by hand manipulation. The collected semen was immediately diluted equally with the solution (20% of dried milk: 3; 6% of glucose: 1; Seminan-A: 1and 600-900 units/ml of penicillin), and then was cooled slowly to 5°C. The semen was diluted repeatedly at 5°C with the solution addedto glycerol (4% of mixture volume)making concentration of 3-6 ×10⁶/ml of motile spermatozoa and was put into 1 ml-plastic strows. These samples were frozen and stored from 2 to 12 months in liquid nitrogen. 35-50% of progressively motile spermatozoa were estimated after thawing. The thowed frozen-semen was artificially inseminated intracervically to 4 bitches at heat judged by vulval swelling, vaginal hyperaemia and smear, number of days after the onset of bleeding and the estrous behavior.
In three out of four bitches, vulval swelling appeared again after the insemination and healthy pappies were whelped with the frozen semen stored for 2, 9 and 12 months, respectively.

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[in Japanese]

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