Abstract
We studied the uptake of biotin into human peripheral blood mononuclear cells (PBMC) using [3H]biotin and studied the catabolism of biotin in PBMC using [14C]biotin. Over 30 min, [3H]biotin uptake was greater at 37°C than at 25°C (K(T) = 2.6 ± 0.4 nM, maximal velocity = 2.9 ± 0.2 fmol · 106 cells-1 · 30 min-1). Ouabain reduced [3H]biotin uptake to 65% of control values, suggesting that biotin uptake is Na-K-ATPase dependent. Unlabeled biotin and biotin analogs reduced the uptake of [3H]biotin to 22- 70% of control values, suggesting the presence of a competition for a structurally specific biotin transporter. When endocytosis by PBMC was stimulated by various acyl glycerols, [3H]biotin uptake was 40-73% of control values; these data are consistent with the hypothesis that stimulated endocytosis reduces biotin transporter density on the cell surface. During a 168-h incubation, PBMC did not catabolize [14C]biotin.
Original language | English (US) |
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Pages (from-to) | C382-C388 |
Journal | American Journal of Physiology - Cell Physiology |
Volume | 275 |
Issue number | 2 44-2 |
DOIs | |
State | Published - Aug 1998 |
Externally published | Yes |
Keywords
- 1,2-dioctanoyl-sn-glycerol
- Endocytosis
- Sodium-potassium- adenosinetriphosphatase
ASJC Scopus subject areas
- Physiology
- Cell Biology