Gobbetti A, Zerani M, Mosconi G, Botte V
Department of Cellular Biology, University of Camerino, Italy.
Gen Comp Endocrinol. 1991 Oct;84(1):9-15. doi: 10.1016/0016-6480(91)90059-f.
The present investigation was performed to evaluate the effects of mammalian gonadotropin-releasing hormone (mGnRH) on prostaglandin F2 alpha (PGF2 alpha) plasma level in adult male and female water frog, Rana esculenta, during three different periods of the reproductive cycle: recovery period (October), breeding period (May), and postreproductive period (June). Intact, hypophysectomized (HYP), gonadectomized (GON), and hypophysectomized-and-gonadectomized (HYP/GON) animals were injected with 0.6 micrograms of mGnRH and sacrificed 1 hr and 5 hr after peptide administration. Some of each of the groups were sacrificed without having received mGnRH. PGF2 alpha plasma levels were assessed by radioimmunoassay. Hypophysectomy induced a significant increase of PGF2 alpha levels in October and June males. mGnRH induced a significant increase of PGF2 alpha plasma levels only in HYP and HYP/GON frogs. The tissue target of this GnRH action is, at present, unknown, although interrenals could be putative responsive tissues. At present, it is also difficult to assign any physiological role to observed phenomena unless to suppose that the pituitary inhibition is not constant throughout the year. It cannot be excluded that the prostaglandin induction depends on a local paracrine action of GnRH, which could be performed outside any pituitary control.
本研究旨在评估哺乳动物促性腺激素释放激素（mGnRH）对成年雄性和雌性食用蛙（Rana esculenta）在生殖周期三个不同阶段：恢复期（10月）、繁殖期（5月）和繁殖后期（6月）血浆中前列腺素F2α（PGF2α）水平的影响。完整、垂体切除（HYP）、性腺切除（GON）以及垂体切除并性腺切除（HYP/GON）的动物被注射0.6微克mGnRH，并在注射肽后1小时和5小时处死。每组中的一些动物在未接受mGnRH的情况下被处死。通过放射免疫测定法评估PGF2α血浆水平。垂体切除导致10月和6月雄性动物PGF2α水平显著升高。mGnRH仅在垂体切除和垂体切除并性腺切除的蛙中导致PGF2α血浆水平显著升高。目前，这种GnRH作用的组织靶点尚不清楚，尽管肾上腺可能是假定的反应组织。目前，也很难为观察到的现象赋予任何生理作用，除非假定垂体抑制并非全年恒定。不能排除前列腺素的诱导依赖于GnRH的局部旁分泌作用，这可能在任何垂体控制之外进行。
