McAsey M E, Machen N, Benson B
Department of Cell Biology and Anatomy, University of Arizona, Tucson 85724, USA.
Life Sci. 1995;57(22):2057-71. doi: 10.1016/0024-3205(95)02190-t.
Inhibin is a heterodimeric glycoprotein which may regulate FSH synthesis and secretion as well as follicular development and maturation. The source and physiological role of inhibin have not been established for the hamster, although several investigators have suggested that this hormone may function in the regulation of FSH in this species. The major objectives of the present studies were to develop a radioimmunoassay (RIA) for the measurement of inhibin in hamster serum and tissue, to identify the primary source of inhibin and to examine the relationship between inhibin and FSH during the estrous cycle. A sensitive, accurate and specific RIA was developed and utilized to measure changes in circulating levels of immunoreactive inhibin (ir-inh-alpha) following bilateral gonadectomy and throughout the estrous cycle. Circulating ir-inh-alpha declined rapidly and significantly following bilateral gonadectomy in female hamsters suggesting a gonadal source. Serum FSH concentrations increased following the decline in serum ir-inh-alpha levels. In the adult female hamster circulating ir-inh-alpha increased gradually throughout diestrus, peaked at the time of the preovulatory gonadotropin surge, then declined to a nadir on the morning of estrus. Changes in ovarian inhibin subunit mRNAs were examined throughout the estrous cycle and correlated with changes observed in circulating ir-inh-alpha levels. Observed significant reductions in the relative amount of inhibin mRNAs and serum concentrations of ir-inh-alpha during early estrus may moderate the amount and duration of the secondary FSH rise and thus contribute to the regulation of follicle recruitment in the hamster.
抑制素是一种异二聚体糖蛋白，可能调节促卵泡激素（FSH）的合成与分泌以及卵泡的发育和成熟。尽管有几位研究者认为这种激素可能在仓鼠中发挥调节FSH的作用，但抑制素在仓鼠中的来源和生理作用尚未明确。本研究的主要目的是开发一种放射免疫分析法（RIA）来测定仓鼠血清和组织中的抑制素，确定抑制素的主要来源，并研究发情周期中抑制素与FSH之间的关系。我们开发并利用了一种灵敏、准确且特异的RIA来测量双侧性腺切除后及整个发情周期中免疫反应性抑制素（ir-inh-alpha）循环水平的变化。雌性仓鼠双侧性腺切除后，循环中的ir-inh-alpha迅速且显著下降，提示其来源于性腺。血清ir-inh-alpha水平下降后，血清FSH浓度升高。在成年雌性仓鼠中，循环中的ir-inh-alpha在间情期逐渐升高，在排卵前促性腺激素高峰时达到峰值，然后在发情期早晨降至最低点。在整个发情周期中检测卵巢抑制素亚基mRNA的变化，并将其与循环中ir-inh-alpha水平的变化进行关联。发情早期观察到抑制素mRNA相对量和ir-inh-alpha血清浓度显著降低，这可能会调节FSH二次升高的量和持续时间，从而有助于调控仓鼠卵泡的募集。
