Anis Y, Zisapel N
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel.
Mol Cell Endocrinol. 1991 Apr;76(1-3):23-34. doi: 10.1016/0303-7207(91)90256-r.
The effects of castration on 2-[125I]iodomelatonin ([125I]melatonin) binding sites in discrete brain areas were investigated in male Syrian hamsters exposed to long and short days. In hamsters maintained in long days (14 h light: 10 h darkness), castration produced a marked decrease in [125I]melatonin binding in the brain, particularly in the medulla-pons hypothalamus and hippocampus. Maximal response in the medulla-pons and hypothalamus was observed at 3 days; specific [125I]melatonin binding subsequently increased to reach control levels within 30 days after castration. In the hippocampus, the decrease in [125I]melatonin binding was still evident at 90 days after castration and could be reversed by testosterone. Exposure to short days (8 h light: 16 h darkness) did not affect [125I]melatonin binding in the various brain areas of the intact hamsters; even after 90 days when circulating testosterone decreased to castrated levels, the binding remained as in intact, long-day-housed controls. Moreover, [125I]melatonin binding in the various brain areas of hamsters exposed to short days was unaffected by castration. The results clearly indicate that the regulation by testosterone of melatonin receptors in the medulla-pons, hypothalamus and hippocampus of the male hamster depends on the prevailing photoperiod.
研究了去势对处于长日照和短日照条件下的雄性叙利亚仓鼠离散脑区中2-[¹²⁵I]碘褪黑素（[¹²⁵I]褪黑素）结合位点的影响。在处于长日照（14小时光照：10小时黑暗）条件下饲养的仓鼠中，去势导致脑中[¹²⁵I]褪黑素结合显著减少，尤其是在延髓-脑桥、下丘脑和海马体中。在延髓-脑桥和下丘脑观察到3天时出现最大反应；去势后30天内，特异性[¹²⁵I]褪黑素结合随后增加至达到对照水平。在海马体中，去势后90天时[¹²⁵I]褪黑素结合的减少仍然明显，并且可以被睾酮逆转。暴露于短日照（8小时光照：16小时黑暗）对完整仓鼠的各个脑区中[¹²⁵I]褪黑素结合没有影响；即使在90天后循环睾酮降至去势水平时，结合情况仍与处于长日照条件下饲养的完整对照仓鼠相同。此外，暴露于短日照的仓鼠各个脑区中的[¹²⁵I]褪黑素结合不受去势影响。结果清楚地表明，雄性仓鼠延髓-脑桥、下丘脑和海马体中褪黑素受体受睾酮的调节取决于当时的光周期。
