Iwata N, Hara S, Nishimura C, Takahashi M, Mukai T, Takayama M, Endo T
Department of Forensic Medicine, Tokyo Medical College, Japan.
Eur J Biochem. 1996 Jan 15;235(1-2):444-8. doi: 10.1111/j.1432-1033.1996.00444.x.
The physiological roles of aldose reductase [alditol:NAD(P)+1-oxidoreductase] have not been fully elucidated yet, although it has been implicated in the pathogenesis of diabetic complications. In the rat ovary we found remarkable changes in the enzyme level during the 4-day estrous cycle. After diestrus, the activity and protein content of aldose reductase increased to the maximum level on proestrous morning and rapidly fell off to the lowest level on the early morning of estrus. At this time its mRNA level in the ovary was significantly decreased compared with that on the morning of proestrus. Immunohistochemical staining of the diestrous ovary demonstrated localization of the enzyme protein in the granulosa cells and in the oocytes. At the end of proestrus when its level was low, immunoreactive aldose reductase in the granulosa cells was localized preferentially to the antrum side, with lesser staining in the cells lining the follicles. Administration of chlorpromazine to the rats on proestrus significantly restored the enzyme level on the following morning of the expected estrus. This effect of chlorpromazine was abolished when human chorionic gonadotropin was administered to the chlorpromazine-treated rats. When chlorpromazine was administered to the rats treated with bromocriptine, an inhibitor of pituitary prolactin secretion, aldose reductase activity in the ovary was significantly elevated compared with that in the rats treated with chlorpromazine alone. These findings suggest that in the rat ovary it is under hormonal regulation during the estrous cycle. The enzyme may possess a new functional role in the reproductive system of the female rat, which can be disordered under diabetic conditions.
醛糖还原酶[醛糖醇:NAD(P)+1-氧化还原酶]的生理作用尚未完全阐明，尽管它与糖尿病并发症的发病机制有关。在大鼠卵巢中，我们发现该酶水平在4天的发情周期中发生了显著变化。动情后期过后，醛糖还原酶的活性和蛋白质含量在动情前期早晨升至最高水平，并在发情期清晨迅速降至最低水平。此时，其在卵巢中的mRNA水平与动情前期早晨相比显著降低。动情后期卵巢的免疫组织化学染色显示该酶蛋白定位于颗粒细胞和卵母细胞中。在动情前期结束时，当该酶水平较低时，颗粒细胞中的免疫反应性醛糖还原酶优先定位于卵泡腔侧，卵泡内衬细胞中的染色较少。在动情前期给大鼠注射氯丙嗪可使预期发情期的次日早晨该酶水平显著恢复。当给氯丙嗪处理的大鼠注射人绒毛膜促性腺激素时，氯丙嗪的这种作用被消除。当给用垂体催乳素分泌抑制剂溴隐亭处理的大鼠注射氯丙嗪时，卵巢中的醛糖还原酶活性与仅用氯丙嗪处理的大鼠相比显著升高。这些发现表明，在大鼠卵巢中，它在发情周期中受激素调节。该酶可能在雌性大鼠的生殖系统中具有新的功能作用，在糖尿病条件下可能会紊乱。
