Effects of insulin and of NSILA-S on the perfused rat heart: glucose uptake, lactate production and efflux of 3-0-methyl glucose.

200 muU of insulin per ml perfusion medium stimulated glucose uptake and lactate production by the isolated perfused rat heart about 5 and 10 fold, respectively. Nonsuppressible insulin-like activity (NSILA-S) extracted from human serum had almost the same maximal effects. Mol per mol the two substances were equally effective and, correspondingly, the dose-response curves were very similar. NSILA-S accelerated the efflux of 3-0-methyl glucose from the heart cells to the same extent as insulin. It can be concluded that NSILA-S acts on heart muscle in a very similar way to that of insulin.