一种用于促黑素肽的灵敏体外蟾蜍皮肤生物测定法。

A sensitive in vitro toad skin bioassay for melanotropic peptides.

Ferroni E N, Castrucci A M

Departamento de Fisiologia Geral, Universidade de São Paulo, Brasil.

Braz J Med Biol Res. 1987;20(2):213-20.

Abstract

An in vitro bioassay for melanotropic peptide utilizing reflectance measurements of toad skin (Bufo ictericus ictericus) is described as an alternative to the commonly used Rana pipiens bioassay. 2. The toad skin bioassay is as sensitive to melanotropins and melanin concentrating hormone (MCH) as the frog bioassay. 3. On the basis of parallel dose-response curves obtained with the toad skin assay we found that beta-MSH is slightly less active than alpha-MSH, whereas the synthetic analogue [Nle4-D-Phe7]-alpha-MSH is about 10 times more potent and exhibits prolonged biological activity. 4. MCH, a putative neurohormone, can also be bioassayed in the in vitro toad skin bioassay, since it has alpha-MSH-like activity on amphibian melanocytes. 5. Since neither adreno- nor cholinoceptors are present in the toad melanocytes, the assay provides great specificity and sensitivity for the determination of melanotropin activity in tissue or blood.

摘要

描述了一种利用蟾蜍皮肤（黄斑蟾蜍）反射率测量来检测促黑素肽的体外生物测定法，作为常用的牛蛙生物测定法的替代方法。2. 蟾蜍皮肤生物测定法对促黑素和黑色素浓缩激素（MCH）的敏感性与青蛙生物测定法相同。3. 根据蟾蜍皮肤测定法获得的平行剂量反应曲线，我们发现β-促黑素细胞激素的活性略低于α-促黑素细胞激素，而合成类似物[Nle4-D-Phe7]-α-促黑素细胞激素的效力约高10倍，且具有延长的生物活性。4. MCH是一种假定的神经激素，也可以在体外蟾蜍皮肤生物测定法中进行生物测定，因为它对两栖类黑素细胞具有α-促黑素细胞激素样活性。5. 由于蟾蜍黑素细胞中既不存在肾上腺素能受体也不存在胆碱能受体，该测定法为测定组织或血液中的促黑素活性提供了很高的特异性和敏感性。