広島大学生物生産学部紀要 Volume 24 Issue 1・2
published_at 1985-11

Inhibitory Effect of Steroid-Free Porcine Follicular Fluid on Ovulation in Rabbits

ステロイド除去豚卵胞液の投与が家兎の排卵に及ぼす抑制効果について
Yoshida Yasunori
Terada Takato
Tsutsumi Yoshio
Hirata Takehiko
Kanematu Shigeto
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Abstract
活性炭で処理した豚卵胞液(CTPFF)を家兎に投与し、交尾刺激又はhCG投与によ誘起される排卵について検討した。1、CTPFFを5mlずつ8時間おきに15回連続投与(10羽)、又は4mlずつ12時間おきに10回投与(5羽)し、最終投与時に強制的に交尾させたが、処理区は全く排卵せず、対照の生理的食塩水投与区で16羽中4羽が排卵した。交尾後4日目の処理区家兎卵巣では大型卵胞数が有意に減少しており、外陰部の腫脹・潮紅の度合もCTPFF投与開始後1~2日で低下した。末梢血中FSH量の測定結果については(RIA法)、CTPFF処理期間中処理区の全てのサンプルが測定限界値以下であったが、投与終了後1~2日に高い値を示したものがあり、CTPFF処理に対するリバウンド現象が起きている可能性が考えられた。2、4mlのCTPFFを12時間おきに連続10回投与し、hCG10IUを静注したところ、6羽中3羽が排卵し、対照区では8羽中6羽が排卵した。排卵数は処理区で有意に減少していた。非排卵個体の大型卵胞数は処理区で減少していた(hCG投与後4日)。外陰部の状態も投与開始後衰退した。3、前項2と同様に処理し、hCGを15IU投与した。処理区、対照区とも全個体排卵したが、排卵数は処理区で有意に少なかった。hCG投与後7日目の大型卵胞数には両区間で有意差はなかった。外陰部の状態は矢張りCTPFF投与開始後2日目から衰退したが、投写終了後4日目以降回復して両区間に差は認められなくなった。以上の結果、数日間のCTPFF連続授与が家兎の排卵に対して抑制的効果を示し、排卵数をも減少させることが知られた。
Abstract
The effect of successive administrations of charcoal-treated porcine follicular fluid (CTPFF) on ovulation in rabbits was examined.

In group 1, fifteen does mated after receiving 15 injections of 5 ml of CTPFF at 8-hour intervals (treatment A) or 10 injections of 4 ml at 12-hour intervals (treatment B) showed completely suppressed ovulation. Control does which were treated with saline solution ovulated (20% of does in control A and 33% in control B). Non-ovulatect does treated with CTPFF showed a decrease in large follicles (> 1.5 mm size in diameter) 4 days post coitum. Vulvar swelling and coloration receded 1 day (treatment A) and 2 days (treatment B) after the beginning of CTPFF treatments. Follicle-stimulating-hormone (FSH) concentrations in peripheral blood werc examined by radioimmunoassay, but no samples had detectable levels during the treated period in CTPFF groups. But elevation in FSH levels was noted in 4 does in treated groups after treatments.

In group 2, 6 does which had received 10 injections of 4 ml of CTPFF at 12-hour intervals were given 10 IU of hCG, resulting in ovulations in 50%. The same dose of hCG caused ovulation in 75% of control animals (8 does). The number of ovulations was significantly lower in the CTPFF groups than in controls (p < 0.01). Numbers of large follicles were fewer in ovaries of treated non-ovulated does than that in controls 4 days post coitum. Vulvas became smaller and more faded from treatment with CTPFF, also.

In group 3, 15 IU of hCG was used for ovulation induction in 6 does which were treated with CTPFF in the same manner as group 2. This gave rise to ovulation in all does in both treated and control (7 does) groups. However, the number of ovulations was significantly lower in the CTPFF gro~tpt han in the controls (p < 0.01). The appearance of the vulva showed a trend similar to that in groups 1 and 2. But the number of large follicles in ovulated does did not vary at 7 days after the end of CTPFF treatments between treated and control groups. This indicates that follicular development which is inhibited by CTPFF treatments may be resumed by a rebound phenomenon in FSH levels.

It is concluded that successive injections of CTPFF for sevcral days affected ovulation in our rabbits, not only reducing the number of does which ovulated, but also the number of ovulations in does which were caused to ovulate by administration of hCG.