Nonsuppressible insulin-like activity extracted and purified from human serum (NSILA-S) mimics all insulin-like effects in vitro and, after injection, in vivo in the presence of excess insulin antibodies. However, there is no evidence that it exerts acute insulin-like effects in its native form in the circulation, where it is almost completely bound to a specific large molecular weight carrier protein. In this paper we show that partially purified NSILA-S-carrier protein, devoid of endogenous insulin-like activity, inhibits the stimulatory effect of NSILA-S, but not of insulin, on 3-0-methylglucose transport and on lipogenesis from [U-14C]glucose in isolated rat fat cells. Concomitantly, it prevents binding of 125I-labeled NSILA-S to the insulin receptor and to the NSILA-S-binding site.
J. Zapf, E. Schoenle, G. Jagars, I. Sand, J. Grunwald, E. R. Froesch
The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.