Gobbetti A, Zerani M
Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
Gen Comp Endocrinol. 1991 Dec;84(3):434-9. doi: 10.1016/0016-6480(91)90092-k.
The present study was carried out to evaluate the in vitro effects of mammalian gonadotropin-releasing hormone (mGnRH) on the production of prostaglandin F2 alpha (PGF2 alpha) and sex steroids (progesterone, androgens, and 17 beta-estradiol) by the interrenal gland of male and female Rana esculenta during three different periods of the sexual annual cycle. In both sexes, mGnRH induced a significant increase in PGF2 alpha in the incubation medium in all examined periods. Progesterone and androgens were undetectable, while 17 beta-estradiol was significantly increased by mGnRH in interrenals incubated during the postreproductive period in both sexes. These results suggest that R. esculenta interrenals could be a GnRH-dependent PGF2 alpha-secreting tissue. In addition, the simultaneous increase in PGF2 alpha and estradiol from postreproductive cultured interrenals support the notion that mGnRH-induced estradiol synthesis is mediated through PGF2 alpha formation. This finding, taken together with other previous studies, strongly suggests that the end of the breeding period in R. esculenta depends on GnRH-induced PGF2 alpha-mediated enhancement of estradiol synthesis in a steroidogenetic organ (probably interrenals).
本研究旨在评估哺乳动物促性腺激素释放激素（mGnRH）对性成熟周期三个不同阶段的雄性和雌性食用蛙肾上腺分泌前列腺素F2α（PGF2α）和性类固醇（孕酮、雄激素和17β-雌二醇）的体外影响。在所有检测阶段，mGnRH均使两性肾上腺孵育培养基中的PGF2α显著增加。未检测到孕酮和雄激素，而在两性生殖后期孵育的肾上腺中，mGnRH使17β-雌二醇显著增加。这些结果表明，食用蛙肾上腺可能是一种依赖GnRH分泌PGF2α的组织。此外，生殖后期培养的肾上腺中PGF2α和雌二醇同时增加，支持了mGnRH诱导的雌二醇合成是通过PGF2α形成介导的这一观点。这一发现与之前的其他研究一起，强烈表明食用蛙繁殖期的结束取决于GnRH诱导的PGF2α介导的类固醇生成器官（可能是肾上腺）中雌二醇合成的增强。
