Cytoplasmic androgen binding protein of rat liver: molecular characterization after photoaffinity labeling and functional correlation with the age-dependent synthesis of alpha 2u-globulin

Journal Article · Tue Jun 30 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00387a033· OSTI ID:5727503

Sarkar, F H; Sarkar, P K; Hunter, S; Poulik, M D; Roy, A K

The liver of the mature male rat contains a moderate affinity (Kd = 10(-8)M), low-capacity, cytoplasmic androgen binding protein (CAB) whose appearance during puberty and disappearance during senescence correlate with the androgen-dependent synthesis of alpha 2u-globulin. Molecular properties of CAB were examined by photoaffinity labeling with tritiated methyltrienolone (R-1881), a synthetic androgen, and by its localization within the hepatocytes which are competent to produce alpha 2u-globulin. Photoaffinity labeling of the liver cytosol derived from postpubertal male rats, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, showed a predominant androgen binding band corresponding to Mr 31,000. This 31-kilodalton (kDa) binding component was conspicuously absent in the liver of androgen-insensitive prepubertal and senescent male rats and in adult male rats treated with estradiol-17 beta. In addition, unlike the cytoplasmic extract, the nuclear lysate of the male rat hepatocytes did not contain the 31-kDa androgen binder. Disappearance of the 31-kDa androgen binding band from the cytosolic fraction of androgen-insensitive animals was associated with a concomitant appearance of a minor androgen binding component of apparent Mr 29,000. The livers of postpubertal male rats normally contain two subpopulations of hepatocytes, only one of which is highly active (competent) in alpha 2u-globulin synthesis. Separation of these two subpopulations through a fluorescence-activated cell sorter followed by whole cell labeling showed more than a 2-fold higher uptake of R-1881 by the competent cells.

• Research Organization: Oakland Univ., Rochester, MI
• OSTI ID: 5727503
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:13; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AGE DEPENDENCE
ANIMALS
BIOMEDICAL RADIOGRAPHY
BIOSYNTHESIS
BODY
CELL CONSTITUENTS
CYTOPLASM
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
ELECTROPHORESIS
FLUOROSCOPY
GLANDS
GLOBULINS
GLOBULINS-ALPHA
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LABELLING
LIVER
MAMMALS
MEDICINE
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOLOGY
RATS
RODENTS
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES