Taragnat C, Durand P
Station de Physiologie de la Reproduction des Mammifères Domestiques, URA-CNRS 1291, Institut National de la Recherche Agronomique, Nouzilly, France.
Mol Cell Endocrinol. 1993 Oct;96(1-2):7-17. doi: 10.1016/0303-7207(93)90089-3.
Stimulation of sheep fetal gonadotrophs with 10(-7) M luteinizing hormone releasing hormone (LHRH) for 3 h in culture wells increased luteinizing hormone (LH) release over basal values. Using the reverse hemolytic plaque assay (RHPA), we demonstrated that this increase was due to a recruitment of LH-secreting cells. During gestation, the percentage of LH-containing cells able to release and the mean size of plaques were the highest at around 100-130 days and were usually lower in females than in males. In an attempt to delineate the involvement of protein kinase C (PKC) in LH release, cells were treated with an activator of PKC, phorbol 12-myristate 13-acetate (PMA). Stimulation of cells with 10(-6) M PMA for 3 h enhanced LH release in culture wells 2- to 3-fold more than did 10(-7) M LHRH. This increase was a consequence of an enhanced number of LH-secreting cells and, in males only, of an enhancement of the mean plaque size. The percentage of LH-secreting cells among LH-containing cells and the plaque areas were maximal between 110 and 120 days of gestation in both sexes. They were usually lower in females than in males. Stimulation of cells with LHRH plus PMA enhanced LH release in culture wells in an additive manner when compared to either factor alone in both sexes and at all fetal ages. This additive effect reflected an increase in the number of secreting cells. Under these conditions, plaque sizes were larger than the plaque sizes obtained with PMA alone in males and in females in late gestation. In conclusion, our results show that LHRH stimulated LH secretion from sheep fetal cells by recruiting secreting cells when compared to controls. Both 100-120 days of gestation and were higher in males than in females. Results following treatment of cells with PMA, either alone or in combination with LHRH, suggest that these two secretagogues act on two different subpopulations of gonadotrophs and probably through different pathways.
在培养孔中用10⁻⁷ M促黄体生成激素释放激素（LHRH）刺激绵羊胎儿促性腺激素细胞3小时，可使促黄体生成激素（LH）释放量高于基础值。使用反向溶血空斑试验（RHPA），我们证明这种增加是由于LH分泌细胞的募集。在妊娠期间，能够释放LH的细胞百分比和空斑的平均大小在大约100 - 130天时最高，且通常雌性低于雄性。为了阐明蛋白激酶C（PKC）在LH释放中的作用，用PKC激活剂佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）处理细胞。用10⁻⁶ M PMA刺激细胞3小时，与10⁻⁷ M LHRH相比，培养孔中LH释放增强2至3倍。这种增加是由于LH分泌细胞数量增加，且仅在雄性中平均空斑大小增加。两性中，含LH细胞中分泌LH的细胞百分比和空斑面积在妊娠110至120天之间最大。通常雌性低于雄性。与单独使用任一因子相比，在所有胎儿年龄的两性中，用LHRH加PMA刺激细胞可使培养孔中LH释放以相加的方式增强。这种相加效应反映了分泌细胞数量的增加。在这些条件下，妊娠后期雄性和雌性的空斑大小均大于单独用PMA获得的空斑大小。总之，我们的结果表明，与对照相比，LHRH通过募集分泌细胞刺激绵羊胎儿细胞分泌LH。妊娠100 - 120天期间，且雄性高于雌性。用PMA单独或与LHRH联合处理细胞后的结果表明，这两种促分泌剂作用于促性腺激素细胞的两个不同亚群，可能通过不同途径起作用。
