CHANGES IN SERUM INSULIN CONCENTRATION DURING PUBERTY AND THEIR RELATIONSHIP TO GROWTH HORMONE

In 40 tall and short children we have demonstrated using oral glucose tolerance tests that there is an increase in serum insulin concentration during puberty with no change in blood glucose concentration. Fasting serum insulin concentration rose from a pre-pubertal value between 4.0 and 5.7 mU/l to values between 11.0 and 14.6 mU/l during puberty. This rise in both fasting serum insulin concentration and the incremental area under the insulin curve is probably due to changes in circulating GH concentrations. In 16 tall girls a rise in serum GH concentration was observed during pubertal growth and the rise was accompanied by a two- to three-fold increase in fasting serum insulin concentration. In 13 children in whom 24 h growth hormone profiles were recorded higher insulin concentrations were seen in those who secreted the most growth hormone. These data suggest that during pubertal growth in diabetic children the standard dosage of insulin administered (0.9 units/kg per day) should be doubled or possibly tripled to maintain good metabolic control and maximize pubertal growth.