Glycemic response to 24-hour fast in normal children: III. Influence of age.

A 24-hour fast was performed in 28 normal children-17 boys and 11 girls, 2 to 17 years of age. After the fast, blood was drawn for blood sugar, plasma growth hormone and cortisol, serum free fatty acids and alanine measurements. Blood sugar values ranged between 30 and 77 mg/dl and were significantly correlated to age (R = 0.68, P less than 0.001). Plasma cortisol (R = 0.73, P less than 0.001), GH (R = 0.57, P = 0.01), and FFA (R = 0.76, P less than 0.001) were negatively correlated to age. Serum alanine fasting values ranged between 10 and 36 micrometer/dl and were significantly correlated to age (R = 0.86, P less than 0.001) and to blood sugar values (R = 0.54, P less than 0.01). These data demonstrate that carbohydrate regulation during fast improves with age in children, correlating with higher levels of gluconeogenic substrates and a lower rate of lipolysis.