Intravenous metyrapone testing. Evaluation of growth hormone and adrenocorticotrophic hormone in children

G. E. Bacon, R. M. Larson, M. L. Spencer and R. P. Kelch

An intravenous metyrapone tartrate test was performed on 26 children to assess growth hormone (GH) reserve and pituitary-adrenal axis. Results were compared to the response evoked by an estrogen-primed arginine-insulin tolerance test (ATT/ITT). Administration of metyrapone intravenously proved to be a reliable means of evaluating pituitary-adrenal function. However, a normal serum GH concentration (greater than or equal to 7 ng/ml) during the test occurred in only nine of 18 children who had an adequate response to the ATT/ITT, and in three of these, the peak GH level occurred at the start of the infusion. Therefore, this procedure does not appear to be a satisfactory test for GH reserve in children. Further, the discrepancy between time of the peak serum concentrations of compound S and GH following intravenous administration of metyrapone does not support the contention that the rise of GH level during stress is secondary to release of adrenocorticotrophic hormone.