Characterization of rat leydig cell gonadotropin receptor structure by affinity cross-linking

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5019900

Zhang, Q Y; Hwang, J; Menon, K M.J.

The gonadotropin receptor from rat leydig cell has been characterized with respect to binding kinetics and physiological regulation. The present study was intended to examine the structure of the receptor. Leydig cell suspension was prepared by either collagenase digestion or by mechanical disruption of the testis. The cells were incubated with /sup 125/I-hCG and the unreacted hCG was removed by centrifugation. The /sup 125/I-hCG was then covalently linked to the cell surface receptor using cleavable (dithiobis (succinimidyl propionate)) and non-cleavable (disuccinimidyl suberate) cross-linking reagents. The extracted cross-linked membrane proteins were resolved on SDS-polyacrylamide gels under reducing and non-reducing conditions and subjected to autoradiographic analysis. Under non-reducing conditions, two labeled species with M/sub r/ = 87,000 and 120,000 were detected. However, only one labeled band was detected under reducing conditions with M/sub r/ = 64,000. The binding of /sup 125/I-hCG to the receptor was inhibited by hCG and LH, but not by a number of peptides and proteins. The data suggest that hCG receptor in leydig cell is an oligomeric complex consisting of four subunits, ..cap alpha cap alpha beta gamma... The ..beta.. and ..gamma.. subunits are each linked to an ..cap alpha.. subunit through disulfide linkage and the hormone binds to each ..cap alpha.. subunit. The two dimers formed (..cap alpha beta cap alpha gamma..) are associated by noncovalent interactions.

• Research Organization: Univ. of Michigan, Ann Arbor
• OSTI ID: 5019900
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
COVALENCE
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
GONADOTROPINS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
VERTEBRATES