Insulin secretion coeffiecient is quite a valuable test for studying beta cell function. It was increased in obesity and acromegalics and diminished in maturity-onset diabetes and hyperlipoproteinemia type IV. We were unable in this work to establish any correlation between insulinemia and insulinuria. No relation was also observed between clearances of insulin and creatinine. Immunoreactive insulin is also present in human seminal fluid in a concentration of approximately 45,0 uU/ml.