The insulin secretion and utilization dynamics have been investigated in 35 six weeks old healthy piglets in order to find the connection with spontaneous hypoglycemia. The trial to load piglets with insulin showed an average time t1/2 = 4.93 minutes accepted as normal in 10 piglets with the mean increase in body weight equal to 0.19 kg/day, prolonged time t1/2 = 7.56 minutes in 7 piglets with the decreased gain of body weight to 0.108 kg/day, and short time t1/2 = 2.78 minutes with the poor gain of body weight in 6 piglets at the age of 6 weeks. In 10 weeks old piglets the noted time t1/2 was 14.7 minutes. The trial to load piglets with L-arginine--HC1 showed a high insulin secretion amounting to 105.5 microU/ml of plasma in 3 piglets only, assumed as correct, and a low insulin secretion amounting to an average of 20.5 microU/ml of plasma in 10 piglets corresponding, according to the criteria of diagnostics, to the subclinical form of human diabetes mellitus. The glucose tolerance test enabled to distinguish 7 strongly reacting piglets (over 100 microU/ml of plasma), 10 moderately responding piglets (from 20 to 100 microU/ml), and 2 piglets not responding (16 microU/ml) by means of increase in insulin concentration. The differentiated results with the individuals deviations to subclinical values observed in healthy piglets, point to serious difficulties in the maintenance of the equilibrium between insulin secretion and utilization. Excessive secretion lasting over 2 hrs and very fast utilization of insulin as well as the level of glucose not compensated by gluconeogenesis, can be the cause of hypoglycemia.