Effects of chronic administration of vanadate to the rat on the sensitivity of glycolysis and glycogen synthesis in skeletal muscle to insulin.

Male Wistar rats were given sodium orthovanadate in their drinking water for at least 14 days. This treatment increased the hypoglycaemic effect of intravenously administered insulin and increased the sensitivity of isolated soleus muscle strips to insulin with respect to both glycolytic and glycogen synthetic rates. This effect of chronic vanadate administration was shown not to be a consequence of a change in the insulin binding characteristics of soleus muscle. It is suggested that these changes may be brought about by the interaction of vanadate with insulin-mediated alterations in tyrosine kinase/phosphotyrosyl phosphatase activities.