Aggarwal B B, Farmer S W, Papkoff H, Stewart F, Allen W R
J Endocrinol. 1980 Jun;85(3):449-55. doi: 10.1677/joe.0.0850449.
Serum of the pregnant donkey, like that of the mare, contains a gonadotrophin of chorionic origin. The chorionic gonaditrophin of the donkey (dCG) has been isolated in purified form from the serum of pregnant donkeys using methodology previously employed for the purification of pregnant mare chorionic gonadotrophin (eCG). Unlike eCG, dCG is predominatly an LH in biological tests. In the in-vitro rat Leydig cell assay, dCG was as active as eCG, but in the in-vitro rat seminiferous tubule assay for FSH and in the augmentation assay, dCG was considerably less potent than eCG (1-10%). Specific rat testis radioreceptor assays for LH and FSH also showed dCG to be at least nine times more potent in LH than in FSH activity. Chemically, dCG was found to be similar to eCG in fractionation behaviour and glycoprotein nature. However, dCG had significantly less carbohydrate (31%) than had eCG (45%) and several differences were noted in a comparison of amino-acid compositions. A single amino-terminal residue, phenylalanine, was detected in dCG. Immunologically, dCG cross-reacted in homologous radio-immunoassays for eCG, equine LH and equine FSH, but its inhibition curves were all nonparallel with those of the respective equine gonadotrophin standards.
怀孕母驴的血清，与母马的血清一样，含有一种源自绒毛膜的促性腺激素。已使用先前用于纯化孕马绒毛膜促性腺激素（eCG）的方法，从怀孕母驴的血清中以纯化形式分离出驴绒毛膜促性腺激素（dCG）。与eCG不同，dCG在生物学试验中主要是一种促黄体生成素（LH）。在体外大鼠睾丸间质细胞试验中，dCG与eCG活性相当，但在体外大鼠生精小管FSH试验和增强试验中，dCG的效力比eCG低得多（1 - 10%）。针对LH和FSH的特异性大鼠睾丸放射受体试验也表明，dCG在LH活性方面至少比在FSH活性方面强九倍。在化学性质上，发现dCG在分级行为和糖蛋白性质方面与eCG相似。然而，dCG的碳水化合物含量（31%）明显低于eCG（45%），并且在氨基酸组成比较中发现了一些差异。在dCG中检测到单个氨基末端残基苯丙氨酸。在免疫学上，dCG在针对eCG、马LH和马FSH的同源放射免疫测定中发生交叉反应，但其抑制曲线与相应马促性腺激素标准品的抑制曲线均不平行。
