Comparative kinetics of the turnover rates of vitamin D/sub 2/ and vitamin D/sub 3/ and their metabolites in chick plasma

Journal Article · Wed Jan 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6796962

Hoy, D A; Horst, R L

Studies regarding the discrimination between vitamin D/sub 2/ and vitamin D/sub 3/ by chickens have led to conflicting conclusions. To investigate this problem in more detail the authors administered radiolabeled vitamin D and vitamin D metabolites, which allowed them to determine their relative plasma clearance rates. The study involved 3 groups of adult male chickens (5/group). Group I received (/sup 3/H)-vitamin D/sub 2/ (1.2 Ci/mmole) and (/sup 3/H)-vitamin D/sub 3/ (1.2 Ci/mmole). Group II received (/sup 3/H)-25-OHD/sub 2/ (90 Ci/mmole) and (/sup 3/H)-25-OHD/sub 3/ (90 Ci/mmole). Group III received (/sup 3/H)-1,25-(OH)/sub 2/D/sub 3/ (90 Ci/mmole) and (/sup 3/H)-1,25-(OH)/sub 2/D/sub 2/ (90 Ci/mmole). The (/sup 3/H)-sterols were co-dosed within each group. The results indicated that the turnover rates of (/sup 3/H)-vitamin D/sub 2/ and (/sup 3/H)-vitamin D/sub 3/ were not significantly different. However, the plasma turnover of the 25 hydroxylated metabolites differed, with (/sup 3/H)-25-OHD/sub 2/ clearing faster (2-4X) than (/sup 3/H)-25-OHD/sub 3/. The largest difference appeared in the 1,25-(OH)/sub 2/D turnover rates with 1,25-(OH)/sub 2/D/sub 2/ clearing approximately 10X faster than (/sup 3/H)-1,25-(OH)/sub 2/D/sub 3/. These data, therefore, indicate that discrimination against vitamin D/sub 2/ sterols in the chick occurs primarily between steps in the metabolism of vitamin D and not at the point of the parent vitamin.

• Research Organization: Dept. of Agriculture, Ames, IA
• OSTI ID: 6796962
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIRDS
BLOOD-PLASMA CLEARANCE
CHICKENS
CLEARANCE
COMPARATIVE EVALUATIONS
FOWL
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
METABOLISM
METABOLITES
REACTION KINETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES
VITAMIN D
VITAMINS