HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rathnam, P. Articles by Saxena, B. B Search for Related Content PubMed Articles by Rathnam, P. Articles by Saxena, B. B

Identification of luteinizing hormone receptor binding inhibitor in bovine corpora lutea

Rathnam P, Lin S, Saxena BB. Identification of luteinizing hormone receptor binding inhibitor in bovine corpora lutea. Eur J Endocrinol 1995;132:213–17. ISSN 0804–4643

A 7000 g supernatant, obtained during the purification of luteinizing hormone (LH) receptor from bovine corpora lutea homogenate, was concentrated by ultrafiltration. The filtrate, containing < 50 000 molecular weight material, exhibited LH receptor binding inhibitor (LH-RBI) activity. The filtrate was ultrafiltered sequentially through Amicon PM-10, PM-30 and UM-2 filters to yield a LH-RBI-containing fraction in the higher molecular weight range of 30 000–10 000 and a LH-RBI-containing fraction in the lower molecular weight range of 10 000–1000. The higher molecular weight LH-RBI fraction was purified on Sephadex G-25 and the lower molecular weight LH-RBI fraction was purified on Sephadex G-50. Both the high- and the low-molecular-weight LH-RBI species inhibited the binding of ¹²⁵I-labeled human chorionic gonadotropin (hCG) to bovine corpora lutea and to rat Leydig cell membrane receptors. Similarly, the production of testosterone by hCG-stimulated rat Leydig cells was inhibited in a dose–response manner by both the high- and the low-molecular-weight LH-RBI species. The LH-RBI activity in the low-molecular-weight species was stable at 4°C for up to 6 months and at temperatures up to 90°C for 15 mins, whereas the LH-RBI activity of the high-molecular-weight species was stable at 4°C for 15 months and unstable at 60°C after 15 min. The 7000 g supernatant provided a much-needed source to obtain larger than previously reported quantities of LH-RBI for isolation as well as for structure and function studies.

Brij B Saxena, Cornell Univ. Medical College, Rm A-267, 1300 York Ave, New York, NY 10021, USA