1. 1. The effects of insulin and a purified nonsuppresiible insulin-like activity on the metabolism and in particular on protein synthesis of adipose tissue in vitro from [14C]glucose, [14C]pyruvate and [14C]glycine were compared. 2. 2. Both substances significantly stimulated [14C]glucose incorporation into CO2, total lipids and protein. Whereas their effects were the same with regard to CO2 and total lipids, nonsuppressible insulin-like activity was less effective than insulin in its stimulatory action on protein synthesis. 3. 3. Whereas insulin clearly stimulated the incorporation of [14C]pyruvate into protein, nonsuppressible insulin-like activity was without effect. 4. 4. Both substances enhanced the incorporation of [14C]glycine into prottein to approximately the same extent in the presence of pyruvate in the medium. No significant effects were found in the absence of a substrate in the medium. 5. 5. These results are interpreted to mean that: (i) Nonsuppressible insulin-like activity affects glucose and amino acid transport in the same way as insulin. (ii) It is devoid of the additional effect on protein synthesis that is exhibited by insulin, presumably through direct action on translation at the ribosome. © 1969.
