The effects of hypothalamic lesions on the sexual maturation and body growth were studied with male tats.
Electric lesions were placed to male Wistar rats at 2 weeks' old.
A monopolar stainless electrode deinsulated 1 mm at tip was inserted into the hypothalamic region_ and direct current (2 mA, 15 sec) was applied under pentobarbital anaethesia.
All animals were weighed twice a week and were daily examined the head of penis for the time of attainment of matured form (U form). They were killed at 7th week of age. Body weight, body length and weight of various organs (testes, seminal vesicles, prostates, adrenals, thyroids, hypophysis and liver) were measured.
a) In the group with anterior hypothalamic lesions, although the growth was retarded, the day of appearance of "U form" was not different from that of control.
Twenty four out of 37 rats attained to "U form" by 7th week (Mean ± S. D. 44.6 ± 3.0 days, vs. 44.1 ± 2.3 days in 34 out of 42 unoperated rats).
The day of "U form" attainment in unoperated rats was closely linked body weight as indicated in Fig. 1 (Mean ± S. D. 156.9 ± 18.4). In rats with lesions, however, the relation between the occurrence of "U form" and body weight which was shown in unoperated group was not observed.
b) Obese rats with the inhibition of development in the reproductive organs were obtained (6 rats).
In those cases lesions which extended to the arcuate nuclei and the rostral part of the mamillary body were noticed.

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Effect of estrogen administration on ovulation, recovery of ova and fertilization in rabbits treated with PMS were studied. Thirty-five mature Japanese white does, each weighing about 3 kg were used. The method of treatment in this experiment were shown in Fig. 1. The hormone used were PMS (Serotropin; Teikoku Hormone Mfg. Co. Ltd. Tokyo), HCG (Synahorin; ibid) and estradiol benzoate (Ovahormone Benzoate; ibid). The results obtained are as follows.
In rabbits accompanied with 0.05, 0.1, 0.15, 0.2 and 0.5 mg of estradiol at the last PMS treatment, the average number of ovulation points was 22.0, 37.4, 37.4, 30.0 and 37.6, respectively, and the percentage of ova recovered was 81.8, 55.6, 71.7, 81.3 and 72.9%, respectively, and the percentage of ova fertilized was 88.9, 78.0, 78.4, 76.5 and 91.9%, respectively.
In rabbits mated at the 48 hr after last PMS, and accompanied with 0.1 mg of estradiol at the last PMS or at the 24 hr after last PMS, the average number of ovulation points was 36.0 and 34.2 and the percentage of ova recovered was 88.3 and 82.5%, and the percentage of ova fertilized was 99.3 and 93.6%, respectively.
These results suggested that superovulation in the rabbit is able to produce by gonadotropin (PMS) accompanied with 0.1 mg or more of estradiol administration.

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[in Japanese]

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It was investigated on the minimum efficiency by means of biological assay with both uterine weight and hemorrhagic follicles and corpora lutea formation reactions of dd mice to the HCG.
The results were summarized as follows.
1) From the results of investigation with the standard error and confidence interval of 95% by uterine weight reaction and X² test and confidence limit of 95% by hemorrhagic follicles and corpora lutea formation reaction on the relation between the number of mice and the response value using 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 mice per one dosage, respectively, to each dosage of 0.5, 1.0, 1.5, 3.0, 4.5, 6.0 IU of the HCG, the confidence interval was very large with uterine weight reaction in 5 and 10 mice, but the value became small in 15 and 20 mice, and values did'nt became small for increasing even the number of mice is more increased.
This was found distinctly that the response value of hemorrhagic follicles and corpora lutea formation reaction by using 30 mice indicated the value closely related to which used 130 mice.
2) From the results in (1), the investigation were conducted on the assay depend on uterine weight reaction by means of six point assay with dosage of 1.5, 3.0, 6.0 IU respectively using 15 and 20 mice to one dosage. The test was carried by four to four times in group of 15 mice but the potency ratio and the confidence limit of 95% in the tests indicated considerable intervals, and carried by four to four times in group of 20 mice, potency ratio and confidence limit of 95% in the tests obtained the results in the regular range.
The hemorrhagic follicles and corpora lutea formation reaction were investigated on the assay by means of four point assay with dosage of 1.5 and 3.0 IU using 15 and 30 mice per one dosage, and it was carried the parallelism in both two groups by four times, but the confidence limit of the error was large in group of 15 mice and obtained the results in group of 30 mice was regular range.
From these results, it was found that the uterine weight reaction and hemorrhagic follicles and corpora lutea formation reaction to be used for the biological potency assay of HCG, because reactions have minimum efficiency.

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Recently several reports have indicated that the rapid freezing methods gave fairly good results on livability of bull spermatozoa. The present study was made to investigate various rapid freezing rates from several temperature levels for boar spermatozoa. Semen was collected artificially from three boars and its sperm rich fraction was used for this experiment. Semen was centrifuged at 1500 r.p.m. and separated into sperm and seminal plasma. Sperm portion was resuspended with S-G-S diluent⁶⁾ to give 2×10⁸ total spermatozoa per milliliter of diluted semen. After the semen was cooled down slowly to 10°C, it was extended with S-G-S diluent containing 14% glycerol. Glycerol equilibration was taken place for one hour. The semen was sealed in 1 ml glass ampules. The alcohol bath of control was cooled at the rates of 1°C/min from 10°C to -10°C, 3°C/min from -10°C to -25°C and 5°C/min from -25°C to -79°C. When the temperature of the cooling alcohol bath reached at -5, -10, -20, -30 and -40°C respectively, the experimental samples were transferred directly to the alcohol bath which was kept at -80°C. The samples were thawed in a water bath which was kept at 10°C.
The percentage of live sperm were microscopically estimated at 38°C immediately after thawing (Table 1).
The mean percentage of live spermatozoa decreased with the following order regardless the storage periods;
control>-40>-30>-20>-10>-5°C.
There were statistically significant (P<0.01) differences among these groups (Table 2 and Figure 1).
The changes of the temperature of the samples were recorded by the thermoelectric thermometer (Figure 2).
The results indicated that the rapid cooling down to -80°C from the temperature range between -5°C and -30°C was detrimental to the livability of boar spermatozoa.

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The persistent-estrus rats (P-E rats) which have shown continuous estrus for three weeks after 90 days of age were selected from the andogen-sterilized rats. Ovulation of P-E rats was induced by a single injection of 25 IU of HCG.
The ovaries of P-E rats contained many follicles in various stages of development, but no corpus luteum. This indicates the absence of the ovulatory discharge of luteinizing hormone in the P-E rats.
Following to the artificial ovulation P-E rats showed diestrus within 48 hours and returned to continuous estrus within 8 days after the injection. The animals (either normal or P-E rats) bearing a isotransplanted pituitary gland of P-E rat under the renal capsule showed a pseudopregnancy-like prolongation of diestrus after ovulation. P-E rats which received daily injections of reserpine (0.15 mg /Kg of body wt) for 13 or 20 days showed diestrus and maintained large corpora lutea throughout the injection period. These results suggest that the pituitary gland of P-E rats as well as that of cyclic rats is able to secrete prolactin and receives inhibitory influencence of the central nervous system on the secretion of prolactin.
Daily injections of reserpine for more than seven days were necessary to induce a pseudopregnancy like diestrus in P-E rats, while the injections for five days were sufficient to do so in the cyclic rats. This finding seems explainable on the assumption that stimulative period of prolactin necessary to maintain corpora lutea for a pseudpregnancy-like period could be shortened by the synergism of luteinizing hormone.

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