Gordon A, Swartz H, Shwartz H. 3,5,3' Triiodo-L-thyronine stimulates 2-deoxy-D-glucose transport into L6 muscle cells through the phosphorylation of insulin receptor beta and the activation of PI-3k.
Thyroid 2006;
16:521-9. [PMID:
16839253 DOI:
10.1089/thy.2006.16.521]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
3,5,3' Triiodo-L-thyronine (T3) stimulated the uptake of 2-deoxy-D-glucose (2-DOG) into L6 cells, nongenomically, starting at subpicomolar concentrations and reaching a peak at concentrations of 1-10 nM. Stimulation at the peak was usually approximately 250%. The uptake of 2-DOG declined with higher concentrations of T(3). The dose-response curve of insulin is similar in shape to that of T(3), and its peak stimulation can even reach 600% over the control. Wortmannin, an inhibitor of the PI-3k, completely inhibited the stimulation of 2-DOG uptake by T(3), with no effect on the control cells. L6 cells exposed for 10 minutes to T3 resulted in a 200%-300% stimulation of PI-3k, as measured by the production of labeled (32)P-PI-3P. Similar results were obtained with insulin. After incubation for 5 minutes with L6 cells, T(3) increased phosphorylation of the insulin receptor beta subunit; this correlated significantly with the degree of stimulation of 2-DOG uptake at 90 minutes (r = 0.89, p <or= 0.01). These findings suggest that T(3) stimulates the uptake of 2-DOG into L6 muscle cells, in a manner similar to that of insulin.
Collapse