Increased glucose phosphorylating activity ...
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Citation
| Title | Increased glucose phosphorylating activity correlates with insulin secretory capacity of male JCR: LA-corpulent rat islets |
| Author(s) | C. Chan, R. MacPhail, M. Kibenge, J. Russell |
| Journal | Canadian journal of physiology and pharmacology |
| Date | 1995 |
| Volume | 73 |
| Issue | 4 |
| Start page | 501 |
| End page | 508 |
| Abstract | In this study the glucose responsiveness of isolated, overnight-cultured islets of obese LA/N-corpulent (cp/cp) rats was compared with glucose phosphorylating activity to determine whether changes in the function of glucokinase could be identified. Islets from both male and female cp/cp rats showed a left-shifted concentration response to glucose, with EC50 values of 1.5 and 4.6 mM, respectively, compared with 9.2 mM for lean control islets. Islets from cp/cp rats were partially resistant to inhibition by mannoheptulose, a glucokinase inhibitor. Minimum inhibitory concentrations were 10 mM in cp/cp vs. 3 mM in lean rat islets. Glucose phosphorylating potential was markedly increased in islets of male cp/cp, but not female cp/cp, compared with lean rats. The maximal velocity (Vmax) of hexokinase was increased 5-fold, while the Km of glucokinase was significantly decreased, in male cp/cp compared with the lean control islets(3.6 vs. 35.2 mM). The Km for glucokinase was also decreased in female cp/cp rat islets (17.2 mM). The data from male cp/cp rat islets are consistent with the idea that increased glucose phosphorylation capacity can contribute to insulin hypersecretion and an extreme leftward shift in the concentration-response curve. However, other factors must also be considered because female cp/cp rats have moderately increased insulin secretory capacity without marked changes in total glucose phosphorylating capacity. |
| ISSN | 0008-4212 |
Using APA 6th Edition citation style.
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