卵子の体外保存の条件を吟味する基礎実験の一つとして,ラット卵子を用いて(i)保存液,(ii)保存温度,(iii)卵子の発生時期等について,呼吸能を指標として検索した。
保存液としてK.R.P.+0.1%glucose液,CaC₂-free.K.R.P.+0.1%g1ucose液,同種血清及び血清稀釈液を用い,0°C,5°C,10°C及び°Cにそれぞれ1~5日間保存し,各一定時間保存後呼吸能を測定して採卵直後の呼吸能に対する割合を調べた.その結果ラット卵子の保存温度としては5°C,10°Cが良好で,保存液としては血清,血清稀釈液がよく,発生時期としては2細胞期,4細胞期がよく,発生が進むに伴い呼吸能の低下が大きくなることが認められた。かくして卵子の保存による呼吸能の変化が卵子の活性の判定基準となり得る様に思われた。

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津田沼孵化場における過去9カ年間の総入卵数1,597,683個の孵化成績を検討して,次の結果を得た。
1. 受精率には明確な季節的変化がみられ,交配別にその様相を異にする。すなわち,同品種間交配では春(W:91.31%, N: 89.57%, B: 86.32%)に最も高く,冬(W:85.09%, N:84.72%, B:84.65%)がこれに次ぎ,夏(W:77.65%, N:83.33%, B:82.85%)と秋(W:74.77%, N:83.99%, B:81.04%)に低い。異品種間交配においては,春(WN:89.68%, NW:87.59%, WB:89.21%),夏(WN:86.33%, NW:83.12%, WB:86.27%)の順に高く,秋(WN:81.41%, NW:79.97%, WB:84.53%)と冬(WN:80.48%, NW:80.50%, WB:84.52%)には低い。
2. W,N及びBの孵化率は86.40,85.55,82.76%であるが,異品種間交配WN,NW及びWBの孵化率は87.37,86.37及び84.87%で,WNはW及びNよりも,NWはNよりも優れ,WBはBよりも良好であつた(P<0.01)。またW,N,Bの健全雛率は79.93,78.99.77.79%であるが,これらの異品種間交配WN,NW及びWBのそれは,84.61,82.85,81.05%で,いづれもその両親の属する品種の同品種間交配の場合よりも優れた成績(P<0.01)を示した。これらの結果は艀化の中~後期における発育中止率及び弱雛率の低さに由来する。なお,WNとNWの正逆交配間では,正交配のWNが艀化率,健全雛率共に優れ(P<0.01)ている。
3. 春の孵化率は89.32%で最も高く,次いで冬の88.18%であり,秋(82.33%)と夏(80.78%)は相当低い。健全雛率も同様に,春は86.09%で最も高く,以下冬(84.83%),秋(78.52%),夏(77.11%)の順であつた。
4. 健全雛1,130,629羽の性比は,雄50.47%(P<0.01)であつた。

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卵子のviabilityを判定する一つの方法としてNigrosinを用い,その染色性と呼吸能の関係について検索した。
1) Nigrosinを用い卵子のviabilityを判定するには0.03%~0.06%濃度で5分間処理が良好であることを認めた。
2) 保存卵子について,呼吸能とNigrosinの染色性の関係をみると,呼吸能の低下とNigrosinに染まつてくる卵子数はほぼ一致する傾向のあることを認めた。

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We have been interested in the facts that there are many cases of reproductive disorders in the bulls probably caused by hormonal disturbances. Some of those bulls showed a marked increase of estrogen in urine and in blood. It is still unknown whether those reproductive disorderes in the bulls are caused by endogenous or exogenous estrogen, or by the unbalance between estrogen and androgen. Besides these facts, few reports have dealt with the effects of estrogen on the reproductive function of the bull. We made, therefore, an attempt to produce the experimental damage of reproductive function with estrogen to observe the effect of estrogen on the reproductive disorders.
The data presented here were obtained from 5 bulls. The first bull was injected subcutaneously with 2. 5 mg of diethyl-stilbestrol (DES) daily for 110 days. The second one was treated with 5 mg of DES daily for 35 days. The third one was treated with 5 mg of DES daily for 30 days, and 33 days after the last treatment, he was treated additionally with 10 mg of DES daily for 14 days. Remaining 2 bulls were used as controls. The results of the experiments are as follows.
1) There was no remarkable change in the testicular volume of experimental bulls, but swelling and edema of ostium prepuce were observed only in the third bull.
2) Libido was normal or increased in early stage of.the treatment, but decreased in the latest stage of the treatment, and 2 of the treated bulls showed low libido for long time after the treatment. The ability of ejaculation became poor from the middle stage of the treatment and it took a long time befor ejaculation. They showed poor erection and could not ejaculate before they devoted themselves to mount 5-10 times, and one of them leaked out his semen without manifesting a characteristic thrust.3) The decrease in the volume of semen was observed from the middle of the treatment and it lastedto the last stage of the treatment. 'pH of semen inclined slightly to alkaline at the last stage of thetreatment.
4) The sperm motility gradually became poor and the poorest motility or necrospermia was observed at the last stage of the treatment. The recovery of the sperm motility depended on the period of the treatment, and there was a case that poor motility continued for more than 3 months after the treatment.
5) Decrease of sperm count depended on the doses of DES administrated, but at the last stage of the treatment, it was very remarkable in all treated cases. The time for recovery was controled by the degree of damage in the testicular tissue, and 6 months were necessary for the recovery in case of severely damaged one, but only 3 weeks were enough to recover in case of slightly damaged one.
6) Abnormal sperms increased after the treatment of DES. The rate of abnormal sperms became the highest at the last stage of the treatment and the highest rate continued after the final treatment.In case of the treatment of 5 mg, or 10 mg, most of the abnormal sperms were oflooped tail. In case of the treatment of 2 mg, there were many cases of abnormal head sperms and tailless ones, but few looped tail ones.
7) The contents offructose in semen increased at the beginning of the treatment, but decreased repidly at the last stage of the treatment, and kept its lower value for more thanone month. The contents of 17-ketosteroids in blood showed a similar tendency to that of fructose in semen.
8) Normal semen added with the semen plasma ofa treated bull after going removed its plasma and flushing with glycocitrate, showed the decrease its motility and livabi.lity.

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既報の幼若雌マウスの誘起排卵反応によるHCG検定法²⁾をPMS,FSH,LHについて応用し次の結果を得た。
(1)PMSを皮下に追注すると0.8~2.7IUにかけて排卵が誘起されこの場合排卵陽性率はPMS追注量に支配されその変化に対して鋭敏に反応しPMS検定の可能性を認める。
(II)PMS追注を腹腔注射すると皮下注射の場合よりも反応の感度は上昇し1IU以下のPMSを確実に検出し得る。
(III)FSHもLHも共にこの条件下で排卵を誘起し得る而もFSHはLHよりもむしろ少量で排卵を誘起し得た。又これによりFSH,LH検定の可能性を認める。

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VetrophinのR.U.検定試験をSpragu-Dawleyratを用いず,Wistar-Imamichiratを用い,また体重の範囲も教室の標準配合飼料による標準体重に合わせて,やや軽い動物を用いて行なつたところ,3回の試験のいずれも1R.U.投与区の平均卵巣重量は対照区の約5倍で,6倍を超えなかつた。しかし,0.5R.U.投与よりは1R.U.が明らかに卵巣重量が重くなる上に,1R.U.と2R.U.投与では卵巣重量にはほとんど差が見られなかつた。したがって,1R.U.でほぼ卵巣重量増加の上限値に達したと思われる。

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