Insulin modulates the differentiation and synthetic activity of osteoblasts, but its mechanisms of action are not fully understood. Because @entity9050 also influences osteoblast differentiation and is a cofactor for collagen synthesis, we examined the effects of insulin on the transport and metabolism of @entity620 in osteoblastic cells. UMR-106 @entity35 osteoblast-like cells accumulated @entity9050 intracellularly when incubated with @entity15356 ( @entity45497 ; oxidized @entity620 ). Insulin increased the intracellular concentration of @entity9050 derived from @entity45497 and also increased the initial rates of uptake of @entity45497 and @entity897 , but not that of @entity9050 . A half-maximal effect on @entity45497 uptake was observed with approximately 100 pM insulin, whereas @entity2135 ( @entity2135 ) was less potent. Preincubation with insulin for 6-12 h was required for stimulation, similar to the period needed for increased expression of facilitative hexose transporters ( @entity66737 ). @entity45497 uptake was inhibited by the @entity66737 antagonist @entity2389 as well as by the @entity66737 substrates @entity413 and @entity897 , whereas @entity413 and @entity948 had no effect. We conclude that insulin and @entity2135 stimulate osteoblastic uptake of @entity45497 through facilitative @entity12015 transporters. The relative potency of insulin in stimulating @entity45497 uptake is consistent with mediation by insulin receptors. @entity45497 is reduced to @entity9050 within osteoblasts, maintaining a high intracellular concentration of @entity9050 available for collagen synthesis. Impaired uptake of @entity45497 may contribute to the @entity2331 associated with @entity1723 . In addition, cytotoxic levels of @entity45497 may accumulate in the extracellular fluid due to decreased transport activity and competitive inhibition by elevated concentrations of @entity413 .

Insulin stimulates @entity620 recycling and XXXX accumulation in osteoblastic cells.

@entity45497 :: ('CHEBI:27956', 'Chemical') :: ['DHAA'] @entity897 :: ('MESH:D003847', 'Chemical') :: ['2-deoxyglucose'] @entity620 :: ('MESH:D001205', 'Chemical') :: ['vitamin C'] @entity948 :: ('MESH:D005632', 'Chemical') :: ['fructose'] @entity12015 :: ('CHEBI:18133', 'Chemical') :: ['hexose'] @entity66737 :: ('24398(Tax:10116)', 'Gene') :: ['GLUT'] @entity2135 :: ('24482(Tax:10116)', 'Gene') :: ['insulin-like growth factor I', 'IGF-I'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose', 'L-glucose', 'D-glucose'] @entity2389 :: ('MESH:D003571', 'Chemical') :: ['cytochalasin B'] @entity2331 :: ('MESH:D001851', 'Disease') :: ['osteopenia'] @entity1723 :: ('MESH:D003922', 'Disease') :: ['type I diabetes'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity15356 :: ('MESH:D003683', 'Chemical') :: ['dehydroascorbic acid'] @entity9050 :: ('CHEBI:38290', 'Chemical') :: ['ascorbate']
@entity9050 :: (CHEBI:38290,Chemical) :: ['ascorbate']
