Serum free insulin concentrations during the treatment of diabetic coma and precoma with low dose intramuscular insulin.

Fifty patients in diabetic coma or precoma, 33 of whom had previously received insulin and had circulating insulin antibodies, were studied during treatment with a low-dose intramuscular insulin regime. In the presence of insulin antibodies, serum free insulin was separated from bound insulin by steady-state gel filtration. The initial mean serum free insulin concentration in the group of patients without insulin antibodies was 9 mU/1, 1 to 2 hours after intramuscular therapy it had risen to 22 mU/1, and after 7 to 8 hours to 73 mU/1. The corresponding concentrations for the group with insulin antibodies were 13, 23 and 74 mU/1. No relationship was found between the concentrations of serum free insulin attained and the age of the patients, their initial degree of acidosis, dehydration, and systolic blood pressure, the insulin antibody characteristics of their sera, nor the rate of decline of the blood glucose.