Ferruz J, Barria A, Galleguillos X, Lara H E
Department of Biochemistry and Molecular Biology Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago.
Biol Reprod. 1991 Oct;45(4):592-7. doi: 10.1095/biolreprod45.4.592.
Experiments were undertaken to define the role of gonadotropins in the release of norepinephrine and the relationship with beta-receptors of the ovary. Rat ovaries were removed at different stages of the estrous cycle and incubated in [3H]norepinephrine. Subsequently, ovaries were electrically stimulated and the release of [3H]norepinephrine was recorded. There were no changes in the norepinephrine content during the estrous cycle. The ovary exhibited cyclical variation in norepinephrine-induced release during the estrous cycle. The lowest release of norepinephrine was found during diestrus; there was an increase during proestrus and estrus followed by a decline during metestrus. The release of norepinephrine changed in the opposite way to the beta-receptor number, suggesting a process involving down-regulation between norepinephrine release and beta-receptors of the ovary. Norepinephrine released from the ovary was locally regulated by gonadotropins. The presence of FSH in the superfusion medium stimulated the norepinephrine-induced release from the ovaries of rats in diestrus (by 20%) and estrus (by 40%), but no effect was found during proestrus. In addition, the presence of hCG stimulated (by 40%) norepinephrine-induced release during proestrus, but no changes were apparent during the other stages of the estrous cycle. These results suggest that the local action of gonadotropins on nerve terminals of the ovary might be one of the factors governing the changes in norepinephrine release through the estrous cycle. The changes in the norepinephrine released to the synaptic cleft might exert down-regulation on the beta-adrenergic receptor content of the ovary and in this way control the ovarian steroid secretory activity.
开展实验以明确促性腺激素在去甲肾上腺素释放中的作用以及与卵巢β受体的关系。在动情周期的不同阶段切除大鼠卵巢，并在[3H]去甲肾上腺素中孵育。随后，对卵巢进行电刺激并记录[3H]去甲肾上腺素的释放情况。在动情周期中，去甲肾上腺素含量没有变化。卵巢在动情周期中去甲肾上腺素诱导的释放呈现周期性变化。在间情期发现去甲肾上腺素的释放最低；在发情前期和发情期增加，随后在动情后期下降。去甲肾上腺素的释放与β受体数量呈相反变化，提示在去甲肾上腺素释放与卵巢β受体之间存在下调过程。卵巢释放的去甲肾上腺素受促性腺激素的局部调节。在超灌流培养基中添加促卵泡激素（FSH）可刺激间情期（增加20%）和发情期（增加40%）大鼠卵巢中去甲肾上腺素诱导的释放，但在发情前期未发现作用。此外，人绒毛膜促性腺激素（hCG）的存在在发情前期刺激（增加40%）去甲肾上腺素诱导的释放，但在动情周期的其他阶段未出现明显变化。这些结果表明，促性腺激素对卵巢神经末梢的局部作用可能是在整个动情周期中控制去甲肾上腺素释放变化的因素之一。释放到突触间隙的去甲肾上腺素变化可能对卵巢β-肾上腺素能受体含量产生下调作用，从而控制卵巢甾体分泌活性。
