Lactogen receptors in rat Leydig cells: analysis of their structure with bifunctional cross-linking reagents

Journal Article · Sun Mar 31 23:00:00 EST 1985 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-116-4-1610· OSTI ID:5609519

Bonifacino, J S; Dufau, M L

(/sup 125/I)Iodohuman GH was found to bind to receptors with specificity for lactogenic hormones in a Triton X-100 extract from Leydig cell membranes displaying an affinity constant of 3.8 X 10(/sup 9/) M-1 and a binding capacity of 167 fmol/mg protein. Cross-linking of solubilized (/sup 125/I)iodohuman GH-receptor complexes with disuccinimidyl suberate followed by analysis by sodium dodecyl sulfate-gel electrophoresis in the presence of beta-mercaptoethanol and autoradiography resulted in the appearance of bands with apparent mol wt of 113,000, 103,000, 59,000, and 53,000. The appearance of these bands was prevented by incubation in the presence of lactogenic hormones. By using a two-dimensional electrophoresis technique (first dimension under nonreducing conditions; second dimension under reducing conditions), it was demonstrated that a fraction of the mol wt 59,000 species can be released from the mol wt 103,000 species upon cleavage of disulfide bonds. These results suggest the existence of lactogen receptor species with approximate mol wt of 91,000, 81,000, 37,000, and 31,000 in Triton X-100 extracts from Leydig cell membranes if the contribution of the free hormone (mol wt, 22,000) is subtracted. A fraction of the mol wt 37,000 subunits appears to be contained within the 81,000 species linked through disulfide bonds.

• Research Organization: National Institute of Child Health and Human Development, Bethesda, MD
• OSTI ID: 5609519
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 116:4; ISSN ENDOA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
GONADS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MALE GENITALS
MALES
MAMMALS
MAN
MEMBRANES
MEN
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
PRIMATES
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
STH
TESTES
THIOLS
VERTEBRATES