Insulin and free fatty acid levels during oral glucose tolerance tests and their relation to age in 70 healthy children.

In 70 healthy children aged from three months to 15 years, blood glucose, immunoreactive insulin, and free fatty acids were measured during a three-hour glucose tolerance test. The results are presented for the whole group as well as for three age groups: three months-five years, six-10 years, and 11-15 years. It is demonstrated that (1) glucose levels are significantly lower in young children (younger than five years); (2) there are no significant age-related changes in free fatty acid concentration; (3) insulin levels are increasing constantly and significantly with age, the most strikingly at the age of onset of puberty; the absence of notable changes in glucose tolerance results in a rise of the I/G ratio as well. The causes for the increase of insulin secretion with age, whether of peripheral or pancreatic order, are still speculative.