Itoh M T, Ishizuka B, Kudo Y, Fusama S, Amemiya A, Sumi Y
Department of Chemistry, St. Marianna University School of Medicine, Kawasaki, Japan.
Mol Cell Endocrinol. 1997 Dec 31;136(1):7-13. doi: 10.1016/s0303-7207(97)00206-2.
Melatonin (N-acetyl-5-methoxytryptamine) and the activities of two melatonin-synthesizing enzymes, serotonin N-acetyltransferase (acetyl coenzyme A: arylalkylamine N-acetyltransferase EC 2.3.1.87; NAT) and hydroxyindole-O-methyltransferase (S-adenosyl-L-methionine: N-acetylserotonin-O-methyltransferase EC 2.1.1.4; HIOMT), were assayed in extracts of ovaries obtained from virgin Wistar-derived rats (7-9 week-old) during the light period of a 12 h light/12 h dark cycle. Melatonin was detected in the rat ovary using reverse-phase high-performance liquid chromatography (HPLC) coupled with fluorometric detection and radioimmunoassay (RIA). In addition, NAT and HIOMT activities were found in rat ovary. The apparent Michaelis constants (Km) for the substrates of NAT and HIOMT in the rat ovary were similar to those reported for the pineal gland and retina. These data suggest that the rat ovary, like the pineal gland and the retina, may synthesize melatonin from serotonin by the sequential action of NAT and HIOMT.
在12小时光照/12小时黑暗周期的光照阶段，从初情期Wistar系大鼠（7 - 9周龄）获取的卵巢提取物中，检测褪黑素（N - 乙酰 - 5 - 甲氧基色胺）以及两种褪黑素合成酶——血清素N - 乙酰基转移酶（乙酰辅酶A：芳基烷基胺N - 乙酰基转移酶，EC 2.3.1.87；NAT）和羟基吲哚 - O - 甲基转移酶（S - 腺苷 - L - 甲硫氨酸：N - 乙酰血清素 - O - 甲基转移酶，EC 2.1.1.4；HIOMT）的活性。采用反相高效液相色谱（HPLC）结合荧光检测和放射免疫分析（RIA）法，在大鼠卵巢中检测到了褪黑素。此外，在大鼠卵巢中还发现了NAT和HIOMT的活性。大鼠卵巢中NAT和HIOMT底物的表观米氏常数（Km）与松果体和视网膜报道的相似。这些数据表明，大鼠卵巢与松果体和视网膜一样，可能通过NAT和HIOMT的相继作用，从血清素合成褪黑素。
