Effect of toki-shakuyaku-san on ovulation induced by human menopausal gonadotropin in rats.

One hundred and thirty-five immature female rats were treated with Toki-Shakuyaku-San (TSS:500 mg/kg, Bwt in drinking water) beginning at 25 days of age and continuing during experimental sessions. Fifteen IU of the human menopausal gonadotropin (hMG:Gonadoryl:GNR:GNR 4 contains 4 to 1 ratio of FSH and LH) was injected intraperitoneally on the morning of 28 days of age, and ovulation (presence of tubal ova) was examined on the morning of 29, 30 and 31 days of age. GNR 4 alone induced ovulation at 29 days of age (70%) and at 30 days of age (35%); however, no ovulation was observed at 31 days of age. TSS treatment alone causes 30% to ovulate at 31 days of age. When GNR 4 was combined with TSS treatment, animals demonstrated ovulation at 31 days of age, that is, they ovulated at 29 days of age (93%), at 30 days of age (30%) and at 31 days of age (90%). These results infer that TSS treatment may accelerate the chain of events in the neuroendocrine control on ovulation, thus causing more frequent ovulation in rats.