Antiserum to liver insulin receptor hyperpolarizes rat muscle

Antibodies to insulin receptors have been reported to have some insulinlike metabolic effects. If insulin-induced electrical hyperpolarization of skeletal muscle is part of the transduction chain between receptor and certain metabolic responses, then receptor antiserum should hyperpolarize. The Jacobs antiserum (rabbit antiserum against rat liver insulin receptor) hyperpolarized rat caudofemoralis muscle. Maximum effect, about 4.5 mV, occurred at 1:10,000 dilution, half maximum at about 1:40,000. Maximum effect of antiserum was only as great as half maximum hyperpolarization by insulin on this muscle. 2-Deoxyglucose uptake was also stimulated by antiserum but required greater concentration than for hyperpolarization, and the stimulation was only by about one-third the maximum effect of insulin.