Positive Control of Gonadotropin Secretion by Androgen

我们在单细胞水平上研究了睾酮(T)对雄性大鼠垂体前叶细胞FSH分泌的影响。垂体前叶细胞在10 ng/ml T或未10 ng/ml T的条件下单分散培养72小时，进行细胞免疫印迹法检测卵泡刺激素。通过显微图像分析仪对FSH特异性细胞印迹进行定量。免疫反应细胞印迹在转移膜上检测到的fsh分泌细胞数量增加到孵育6小时，占孵育6小时膜上垂体细胞总数的4.1%。单细胞分泌FSH的量从小于20到大于8000 fg/ cells /h不等。单个细胞的平均FSH分泌量随孵育时间的延长而增加，可达6小时。在孵育的任何时间，在培养基中添加10 ng/ml的T均不会改变FSH分泌细胞的数量。孵育3小时后，T使FSH平均分泌量增加64%，导致单细胞FSH分泌频率分布向右偏移。FSH的总量，即每个FSH分泌细胞分泌的FSH的总和，由于T的增加而增加了92%，其中83.7%的增加是由于最大的分泌亚组（大于5 pg/细胞/3h）的FSH分泌增加。然而，前10个最大分泌亚组的FSH平均分泌量在对照组和t治疗组之间没有差异。本研究首次在单细胞水平上分析了大鼠垂体前叶细胞促卵泡刺激素的分泌。结果表明，T对体外促卵泡刺激素分泌的刺激不是由于促卵泡刺激素分泌细胞数量的增加，而是由于每个细胞促卵泡刺激素分泌的增加。

We investigated the effects of testosterone (T) on FSH secretion from male rat anterior pituitary cells in cultures at the single cell level. Anterior pituitary cells cultured with or without 10 ng/ml T for 72 h were monodispersed and subjected to cell immunoblot assays for FSH.Cell blots specific for FSH were quantified by means of a microscopic image analyzer. The number of FSH-secreting cells detected as immunoreactive cell blots on the transfer membrane was increased up to 6 h incubation and represented 4.1% of total pituitary cells applied on the membrane at 6 h of incubation. The amount of FSH secreted by single cells varied from less than 20 to greater than 8,000 fg/cell/h. The mean FSH secretion from individual cells was increased in an incubation time-dependent manner up to 6 h. The number of FSH-secreting cells was not changed by the addition of 10 ng/ml of T into the culture medium at any time of incubation. T administration increased the mean FSH secretion by 64% after 3 h incubation, resulting in a shift to right in frequency distribution of FSH secretion from single cells. The total amount of FSH namely the sum of FSH secreted by each FSH-secreting cell was increased by 92% by the addition of T and 83.7% of this increase was attributable to an increase in FSH secretion from the largest secretor subgroup (greater than 5 pg/cell/3h). However, mean amounts of FSH secretion by the top 10 of the largest secretor subgroup were not different between control and T-treated groups.The present study analyzed for the first time FSH secretion from rat anterior pituitary cells at the single cell level. The results suggest that stimulation by T of FSH secretion in vitro is not due to the increase in the number of FSH-secreting cells but due to the increase in FSH secretion from each cell.