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Insulin stimulation of glucose entry in cultured human fibroblasts
Author(s) -
Howard Barbara V.,
Mott David M.,
Fields Rose M.,
Bennett Peter H.
Publication year - 1979
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041010115
Subject(s) - insulin , medicine , endocrinology , glycogen , stimulation , hexose , glucose uptake , biology , chemistry , biochemistry , enzyme
Abstract The effect of insulin on glucose entry has been studied in monolayer cultures of human diploid fibroblastic cells. Influence of insulin on total cell glucose incorporation was evaluated using [ 14 C] glucose. Glucose incorporation was increased up to two‐fold in the presence of insulin. Insulin action occurred within 30 minutes and could be observed with insulin concentrations as low as 10 −10 M (10 μU/ml). The action of insulin was enhanced by preincubation in glucose‐free medium. After glucose starvation the cells converted glucose primarily to glycogen and nucleotides, and the stimulation by insulin was observed equally in both fractions. Influence of insulin on the kinetics of hexose transport was studied using 2‐deoxyglucose and 3‐0‐methyl glucose. A large diffusion component was corrected using ρ‐chloromercuribenzoic acid or phloridzin. K m for facilitated diffusion averaged 1.9 mM for 2‐deoxyglucose and 5.3 mM for 3‐0‐methyl glucose, and V max ranged from 10–24 nmoles/min/mg cell protein. Insulin resulted in a 150% increase in V max with no significant change in K m . The data suggest that human diploid fibroblasts can be a useful system for the study of insulin's glucoregulatory action.