多巴胺、雌二醇及睾酮对虎纹蛙离体脑垂体促性腺激素分泌的影响

为了解虎纹蛙促性腺激素分泌的调节机理，用离体静态培育系统和放射免疫测定法，研究了多巴胺（ＤＡ）、雌二醇（Ｅ２）和睾酮（Ｔ）对雌性虎纹蛙离体脑垂体薄片促黄体激素（ＬＨ）和促卵泡激素（ＦＳＨ）分泌活动的影响。结果表明：０．１～１０μｍｏｌ／Ｌ的ＤＡ对成熟前期和冬眠期虎纹蛙离体脑垂体型薄片的ＬＨ及ＦＳＨ的释放都有抑制作用，并且随着ＤＡ浓度的增加，抑制作用逐渐增强。１和１０μｍｏｌ／Ｌ的Ｅ２显著刺激成熟前

EFFECTS OF DOPAMINE,ESTRADIOL AND TESTOSTERONE ON GONADOTROPIN RELEASE FROM THE PITUITARY FRAGMENTS OF Rana rugulosa

To understand the regulatory mechanisms of gonadotropin secretion in Rana rugulosa, this study investigated the effects of dopamina (DA), estradiol (E2) and testosterone (T) on the in vitro release of luteinizing hormone (LH) and follicle-stimulation hormone (FSH) from the pituitary fragments of female Rana rugulosa using a static incubation system and radio-immunoassay (RIA). The results indicated that DA at the concentration from 0.1 μmol/L to 10μmol/L inhibited the release of LH and FSH from the pituitary fragments of sexually pre-mature or hibernation individuals, and the inhibitory effects enhanced with increasing concentrations of DA. E2at 1 μmol/L and 10μmol/L significantly stim-ulated the release of LH of sexually pre-mature individuals, but inhibited their FSH release at 0.1μmol/L to 10 μmol/L; T had no obvious effects on their FSH release, but significantly inhibited their LH release at 10 μmol/L. Neither E2 nor T, at the concentration from 0.1 μmol/L to 100 μmol/L, had obvious effects on the release of LH and FSH of hibernation individuals. The data suggest that DA and sexual steroids may have direct regulatory actions on LH and FSH release at the pituitary level in Rana rugulosa, and the action of sexual sterlids may relate to the gonadal development stages (sea-sons).