Baker B I, Rance T A
Gen Comp Endocrinol. 1983 Jun;50(3):423-31. doi: 10.1016/0016-6480(83)90263-0.
The distribution of melanocyte concentrating hormone (MCH) bioactivity was mapped in the trout brain from cryostat sections cut in several planes. Most of the bioactivity occurred in the ventral third of the hypothalamus, with about 30% of the activity in the dorsal hypothalamus. The bioactivity was rapidly lost if the hypothalami were extracted in dilute acid, with a final extraction pH of 5.2. This loss, which can be avoided if the extract is heated, is presumed to be the result of hypothalamic enzyme activity. Preliminary chemical characterisation indicates that the molecule is a small basic peptide, of less than 2000 daltons (Da) and with an isoelectric point greater than 9.5. MCH bioactivity was also found in the hypothalamus but not the pituitary of Lampetra, Rana, Xenopus, and the rat. The activity from Xenopus and Lampetra had a similar Rf value to MCH from trout during polyacrylamide gel electrophoresis. Partially purified MCH of trout origin, free from MSH bioactivity, induced melanin concentration in eel melanophores but Xenopus melanophores failed to respond.
通过在多个平面切割的低温恒温器切片，绘制了虹鳟鱼脑中黑素细胞集中激素（MCH）生物活性的分布图。大部分生物活性出现在下丘脑腹侧三分之一处，约30%的活性位于下丘脑背侧。如果下丘脑在稀酸中提取，最终提取pH值为5.2时，生物活性会迅速丧失。如果提取物加热，这种丧失是可以避免的，推测这是下丘脑酶活性的结果。初步化学表征表明，该分子是一种小的碱性肽，分子量小于2000道尔顿（Da），等电点大于9.5。在七鳃鳗、蛙、非洲爪蟾和大鼠的下丘脑中也发现了MCH生物活性，但垂体中未发现。在聚丙烯酰胺凝胶电泳过程中，非洲爪蟾和七鳃鳗的活性与虹鳟鱼的MCH具有相似的Rf值。源自虹鳟鱼的部分纯化的MCH，无促黑素（MSH）生物活性，可诱导鳗鱼黑素细胞中的黑色素聚集，但非洲爪蟾黑素细胞无反应。
