Stimulation of peptide synthesis in adipose tissue by insulin without glucose

Abstract

The ability of insulin to stimulate incorporation of histidine-2(ring)-C14 into rat epididymal adipose tissue protein in absence of added glucose was investigated. Insulin alone was without effect, but a significant insulin stimulation was obtained when 10, 20, or 40 mm sodium pyruvate was added to the Krebs-bicarbonate incubation medium. This stimulation was not dependent on traces of glucose, since the pyruvate contained no detectable glucose; moreover, the concentration of glucose required to support the insulin stimulation was found to be not markedly different from that for pyruvate. The conclusion is that the effect of insulin on protein synthesis in adipose tissue is not dependent on any effect it may have on glucose entry.