End product inhibition of hepatic 25-hydroxyvitamin D production in the rat: specificity and kinetics

Journal Article · Thu Oct 31 23:00:00 EST 1985 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(85)90234-6· OSTI ID:6037784

Milne, M L; Baran, D T

The role of vitamin D metabolites in the regulation of hepatic 25-hydroxyvitamin D production was investigated by examining the effects of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D on the synthesis of (25-/sup 3/H)hydroxyvitamin D by rachitic rat liver homogenates. Production of (25-/sup 3/H)hydroxyvitamin D was inhibited by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, but not by 24,25-dihydroxyvitamin D. 25-Hydroxyvitamin D increased the Km of the vitamin D-25-hydroxylase enzyme(s), while 1,25-dihydroxyvitamin D decreased the Vmax with a Ki of 88.7 ng/ml. Inhibition of hepatic 25-hydroxyvitamin D production by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D may be another control mechanism to regulate circulating vitamin D levels.

• Research Organization: Univ. of Massachusetts Medical Center, Worcester
• OSTI ID: 6037784
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 2; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOCHEMISTRY
BIOSYNTHESIS
BODY
CHEMISTRY
DIGESTIVE SYSTEM
DISEASES
GLANDS
KINETICS
LABELLED COMPOUNDS
LIVER
MAMMALS
METABOLIC DISEASES
ORGANS
RATS
RICKETS
RODENTS
SKELETAL DISEASES
SYNTHESIS
TRITIUM COMPOUNDS
VERTEBRATES
VITAMIN D
VITAMINS