| 摘要 |
<p>A 34,500-dalton protein with inhibin activity is isolated from ram rete testis fluid using reverse-phase high-performance liquid chromatography and gel filtration. The isolated molecule is composed of two chains having molecular weights of about 18,000 and about 16,500 Daltons, which are bound together by disulfide bonding and the longer of which is likely glycosylated. Microsequencing revealed the NH2-terminal portion of the 18kD chain to be Ser-Thr-Pro-Pro-Leu-Pro-Trp-Pro-Trp-Ser-Pro-Ala-Ala-Leu-Arg-Leu-Leu-Gln-Arg-Pro-Pro-Glu-Glu-Pro-Ala-Ala-His-Ala-Asp-Cys and of the 16.5kD chain to be Gly-Leu-Glu-Cys-Asp-Gly-Lys-Val-Asn-Ile-Cys-Cys-Lys-Lys-Gln-Phe. This 34.5kD protein specifically inhibits basal secretion of FSH, but not of LH, in a rat anterior pituitary monolayer culture system, exhibiting a half-maximal effective dose of 0.3 ng/ml. Furthermore, antibodies raised against a synthetic replicate of the N-terminal six residues of the 18kD chain are effective to reduce the activity of highly purified 34.5kD ovine inhibin and might be used to exert a profertility effect in rams, ewes and other mammals.</p> |
