Physiology and biochemistry of ovarian inhibin.

There are three recent reports of amino acid sequence studies on inhibin preparations. The preparation obtained in Bombay and partially sequenced by collaborators in Stockholm dealt with a preparation from human seminal plasma. This preparation had a molecular weight of approximately 14,000 (1). On the other hand, Seidah and colleagues in Montreal (2) reported a mixture of four peptides that they sequenced simultaneously to determine 31 of a possible 35 residues in a "complete" peptide. Three of the peptides sequenced as though they were derived from the larger complete peptide. The molecular weight of this peptide was estimated to be 4-5000. In a subsequent paper from this laboratory and two collaborators from the University of California in San Francisco (3), the principal peptide in the mixture was isolated and sequenced (31 residues) and a synthetic peptide with this sequence was shown to have inhibin activity equal to or slightly greater than the native peptide. We will comment further on these studi...