Insulin, growth hormone and carbohydrate tolerance in Jamaican children rehabilitated from severe malnutrition

ABSTRACT

Intravenous glucose tolerance tests were carried out in 20 children (aged 6 - 24 mo) clinically recovered from severe malnutrition. Blood samples were obtained between 10 am and 11 am after 16 hr fast, from a peripheral vein kept patent by a slow infusion of 0.9 percent saline. Samples were taken at timed intervals 0, 1, 2, 3, 5, 7, 10, 20, 30, 40 and 50 min after IV injection of glucose (0.5 g/kg body weight). Plasma insulin, growth hormone, and glucose were measured. Total responses were expressed as the sum of the values at each time point. The mean rate of glucose removal (KG percent/min) was 2.28 +/- 0.13. This is within the normal published range of 2 to 3.5. Four children were < 1 SD below the mean. In these four children, fasting growth hormone and total growth hormone response were significantly higher (p>0.001) than in the others. There was a wide range for fasting growth hormone 1-91 uU/ml. There was a negative correlation between KG and total growth hormone response (r = -0.64, p<0.05, n = 12), and between KG and age (r = -0.61, p<0.01, n = 20). In three children fasting glucose was abnormally low. Neither fasting insulin (3.04 +/- 0.33 uU/ml), fasting glucose (3.9 +/- 0.16 mmol/L) nor insulin response were significantly related to KG. Peak insulin was 28.2 +/_ 2.7 uU/ml and peak glucose was 18.5 +/- 0.6 mmol/L. Seven children showed a delayed (5-10 min) insulin response to glucose 13 had a prompt insulin response 1 min after glucose. The KG of those children who had a delayed insulin response to glucose was normal, but the KG of 2 children with an abnormally low insulin response was below normal. Thus, after anthropometric recovery from malnutrition, 20 percent of children had a low KG, associated with an elevated growth hormone response. In 30 percent of children the insulin response to glucose was delayed, but this was not related to the glucose disappearance rate. In 10 percent of the children, the insulin response to glucose was abnormally low, and this was associated with low KG. In 15 percent of the children, fasting glucose concentrations were abnormally low. Abnormal carbohydrate tolerance was associated with low insulin output and/or elevated growth hormone concentration. (Summary)