DOES RECOMBINANT HUMAN INSULIN-LIKE GROWTH-FACTOR-I HAVE A ROLE IN THE TREATMENT OF DIABETES

The structure of IGF-I is similar to that of insulin, having 43 % sequ ence homology with human proinsulin. Both peptides can induce metaboli c and mitogenic effects through their own specific receptors, which al so share many structural and functional similarities. Primarily involv ed in the regulation of growth, IGF-I may have a role in the control o f glucose homeostasis, facilitated by changes in its binding proteins. RhlGF-I can reduce hyperglycaemia in patients with severe insulin res istance by direct effects mediated via the IGF-I receptor. Improvement s in insulin sensitivity, and reductions in blood glucose levels and H bA1c values have also been seen in subjects with NIDDM. Enhanced insul in sensitivity with low dose rhIGF-I has been observed in adolescents and young adults with IDDM. These effects are closely related to reduc tions in growth hormone levels, but there is also evidence of complex interactions with insulin at the post receptor level and with IGFBP-1. In recent randomised, double-blind, placebo controlled trials, rhIGF- I given as an adjunct to insulin therapy reduced to HbA1c values. Alth ough the ideal dosage to obtain therapeutic efficacy without complicat ions has yet to be determined, rhIGF-I may have an important role in t he treatment of hyperglycaemia and insulin resistance in diabetes. (C) 1997 by John Wiley & Sons, Ltd.