Evidence that synthetic 31-amino acid inhibin-like peptide lacks inhibin activity

L. Liu, J. Booth, G. R. Merriam, K. M. Barnes, R. J. Sherins, D. L. Loriaux, G. B. Cutler

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

We studied the biological activity of a recently characterized 31-amino acid inhibin-like peptide (ILP) using a synthetic preparation. While the material yielded a single component on chromatography, amino acid sequence analysis suggested that only 30% of the molecules possess the complete structure. Bioactivity was tested in vitro using whole pituitaries from 25 day-old male Sprague-Dawley rats. Pituitaries were incubated with 500 ng/ml of the ILP preparation or vehicle alone för 60 min, followed by a 3 h exposure to 2 ng/ml of luteinizing hormone releasing hormone (LHRH) or its diluent. In the ILP-incubated pituitary media, no significant suppression of basal FSH and LH release or stimulated FSH release was observed, while a significant increase in stimulated LH release was seen (p<0.05). An in vivo bioassay study was perförmed on 38 day-old male Sprague-Dawley rats. Test animals were injected with 0.1, 1, 10 or 20 meg of ILP immediately after castration, and 10 and 24 h later. Control animals received bovine serum albumin or vehicle alone. There were no statistically significant differences in serum LH or FSH concentrations taken at 30 h after castration between the ILP-treated rats and controls. Possible reasons för our inability to demonstrate inhibin bioactivity (selective FSH suppression) with this ILP preparation include: 1) Only about 30% of the peptides had the complete amino acid sequence. Other peptides with deletions might have acted as antagonists, thus obscuring the inhibin bioactivity. 2) The 31-amino acid ILP may not be the authentic inhibin molecule. We suggest that further studies are needed to determine the true identity of inhibin.

Original languageEnglish (US)
Pages (from-to)191-197
Number of pages7
JournalEndocrine Research
Volume11
Issue number4 --Mar
DOIs
StatePublished - Sep 1985

ASJC Scopus subject areas

  • Endocrinology

Fingerprint Dive into the research topics of 'Evidence that synthetic 31-amino acid inhibin-like peptide lacks inhibin activity'. Together they form a unique fingerprint.

  • Cite this

    Liu, L., Booth, J., Merriam, G. R., Barnes, K. M., Sherins, R. J., Loriaux, D. L., & Cutler, G. B. (1985). Evidence that synthetic 31-amino acid inhibin-like peptide lacks inhibin activity. Endocrine Research, 11(4 --Mar), 191-197. https://doi.org/10.1080/07435808509032977