Uptake of (/sup 3/H)vitamin D/sub 3/ from low and high density lipoproteins by cultured human fibroblasts

Journal Article · Fri Feb 28 23:00:00 EST 1986 · Proc. Soc. Exp. Biol. Med.; (United States)

DOI:https://doi.org/10.3181/00379727-181-42270· OSTI ID:5690718

Shireman, R B; Williams, D; Remsen, J F

The plasma distribution and cellular uptake of (/sup 3/H)vitamin D/sub 3/ was studied in vitro using cultured human fibroblasts. Incubation of (/sup 3/H)vitamin D/sub 3/ (cholecalciferol) with plasma followed by sequential ultracentrifugal fractionation of the lipoproteins indicated that 2-4% of the radioactivity associated with the very low density lipoprotein (VLDL), 12% with low density lipoprotein (LDL), and approximately 60% with the high density lipoprotein (HDL). The remaining radioactivity, 25%, was associated with the sedimented plasma fractions. By comparison, an average of 86% of the radioactivity from (/sup 3/H) 1,25-dihydroxycholecalciferol associated with the sedimented plasma fractions. The uptake of (/sup 3/H)vitamin D/sub 3/ from plasma, LDL, or HDL was studied in cultured human cells; uptake by normal fibroblasts was greatest from LDL and least from plasma. The cellular association of vitamin D/sub 3/ was time, concentration, and temperature dependent. At a concentration of 50 ..mu..g LDL/ml of medium, the uptake of (/sup 3/H)vitamin D/sub 3/ from LDL at 37/sup 0/C was rapid and reached a maximum at approximately 4 hr; it was slower from HDL but continued to increase slowly up to 24 hr. The significance of these in vitro findings is uncertain since much of the vitamin D/sub 3/ absorbed from the intestine reportedly associates with chylomicrons and is rapidly taken up by the liver.

• Research Organization: Univ. of Florida, Gainesville
• OSTI ID: 5690718
• Journal Information: Proc. Soc. Exp. Biol. Med.; (United States), Journal Name: Proc. Soc. Exp. Biol. Med.; (United States) Vol. 181:3; ISSN PSEBA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ANIMAL CELLS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY FLUIDS
CHOLECALCIFEROL
CONNECTIVE TISSUE CELLS
FIBROBLASTS
IN VITRO
INTESTINAL ABSORPTION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIPIDS
LIPOPROTEINS
MAMMALS
MAN
MATERIALS
METABOLISM
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOACTIVITY
REACTION KINETICS
SOMATIC CELLS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE
VERTEBRATES
VITAMIN D
VITAMINS