Oxberry B A, Greenwald G S
Biol Reprod. 1983 Dec;29(5):1255-63. doi: 10.1095/biolreprod29.5.1255.
Autoradiographic histochemistry was employed to examine changes in the binding of 125I-labeled prolactin (Prl) to ovaries from proestrous hamsters before (at 1200 h), during (at 1600 h), and after (at 2000 h) the preovulatory gonadotropin surge. In untreated control hamsters, there was a marked and progressive loss of Prl binding, first in the interstitial cells and follicular thecae by 1600 h, and then in the granulosa cells of the preovulatory follicles by 2000 h. When proestrous hamsters were treated with ergocryptine to significantly lower serum Prl, or injected with exogenous Prl, Prl binding to their ovaries did not differ from controls, suggesting that decreased Prl binding was due to neither increased occupancy of binding sites by endogenous Prl nor down regulation of Prl receptors by Prl itself. Conversely, when proestrous hamsters were treated with phenobarbital to block the luteinizing hormone (LH)/follicle-stimulating hormone (FSH) surge, the loss of Prl binding sites in the ovaries was prevented, suggesting that the LH/FSH surge might initiate a down regulation of Prl receptors in the ovary. Such a down regulation of Prl receptors may serve as a mechanism by which the ability of Prl to affect periovulatory events in the ovary might be regulated.
采用放射自显影组织化学法，检测动情前期仓鼠在排卵前促性腺激素高峰前（1200时）、期间（1600时）及之后（2000时），其卵巢中125I标记催乳素（Prl）结合情况的变化。在未处理的对照仓鼠中，Prl结合出现显著且渐进性丧失，首先在1600时间质细胞和卵泡膜细胞中出现，然后在2000时排卵前卵泡的颗粒细胞中出现。当给动情前期仓鼠用麦角隐亭处理以显著降低血清Prl，或注射外源性Prl时，其卵巢的Prl结合与对照无差异，这表明Prl结合减少既不是由于内源性Prl对结合位点的占据增加，也不是由于Prl自身对Prl受体的下调。相反，当给动情前期仓鼠用苯巴比妥处理以阻断促黄体生成素（LH）/促卵泡生成素（FSH）高峰时，卵巢中Prl结合位点的丧失得到预防，这表明LH/FSH高峰可能启动卵巢中Prl受体的下调。Prl受体的这种下调可能是一种调节Prl影响卵巢排卵相关事件能力的机制。
