Quantitation of rat liver xanthine oxidase by radioimmunoassay. A mechanism for sex-specific differences

Journal Article · Mon Mar 01 04:00:00 EST 1982 · Arthritis Rheum.; (United States)

DOI:https://doi.org/10.1002/art.1780250310· OSTI ID:5135486

Decker, D E; Levinson, D J

To further delineate the mechanism responsible for the differences in xanthine oxidase activity in male and female Sprague-Dawley rats, a sensitive and specific radioimmunoassay (RIA) was developed for the measurement of hepatic xanthine oxidase. The RIA could detect as little as 5 mg of liver enzyme. Specificity of the RIA was confirmed by 1) Ouchterlony double immuno-diffusion in which a single precipitin band exhibited xanthine oxidase activity, when crude liver homogenate and an enzyme-specific stain were used; 2) parallelism between purified 125I-labeled xanthine oxidase and serial dilutions of crude liver homogenate; 3) a linear correlation between xanthine oxidase activity and the level of enzyme protein; and 4) a single protein band coincident with purified xanthine oxidase, when an immunoprecipitate prepared from antisera and crude liver homogenate was analyzed on sodium dodecyl sulfate (SDS) polyacrylamide gels. Whether xanthine oxidase activity was assayed in the absence of nicotinamide adenine dinucleotide (NAD+) (oxidase form) or in the presence of NAD+ (dehydrogenase), male values were consistently higher, and both forms of the enzyme correlated significantly with each other. When purified to homogeneity, neither form of the enzyme was appreciably affected by 17 beta-estradiol or testosterone propionate. When the RIA was employed, levels of hepatic xanthine oxidase were significantly greater in male than in female rats. We concluded from these data that increased xanthine oxidase activity in the male corresponds to a greater quantitative complement of xanthine oxidase protein. Furthermore, lower xanthine oxidase activity in the female cannot be explained by immunologically cross-reactive material without enzyme activity nor by a direct sex-steroid enzyme interaction.

• Research Organization: Division of Rheumatology, Department of Medicine, Michael Reese Hospital and Medical Center, Chicago, IL
• OSTI ID: 5135486
• Journal Information: Arthritis Rheum.; (United States), Journal Name: Arthritis Rheum.; (United States) Vol. 25:3; ISSN ARHEA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
COENZYMES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
GLANDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIVER
MAMMALS
NAD
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXIDOREDUCTASES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
RATS
RODENTS
SEX DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES