Related Experiment Videos
Intravenous metyrapone testing. Evaluation of growth hormone and adrenocorticotrophic hormone in children
Insights
The intravenous metyrapone tartrate test reliably assesses pituitary-adrenal function in children. However, it is not a satisfactory method for evaluating growth hormone (GH) reserve.
Area of Science:
- Pediatric Endocrinology
- Neuroendocrinology
Background:
- Assessing growth hormone (GH) reserve and pituitary-adrenal axis function is crucial in pediatric endocrinology.
- The metyrapone test is used to evaluate the hypothalamic-pituitary-adrenal (HPA) axis.
Purpose of the Study:
- To evaluate the efficacy of an intravenous metyrapone tartrate test in assessing growth hormone (GH) reserve and pituitary-adrenal function in children.
- To compare the metyrapone test results with those of an estrogen-primed arginine-insulin tolerance test (ATT/ITT).
Main Methods:
- An intravenous metyrapone tartrate test was administered to 26 children.
- Results were compared to responses from an estrogen-primed arginine-insulin tolerance test (ATT/ITT).
Main Results:
- Intravenous metyrapone administration was a reliable method for evaluating pituitary-adrenal function.
- Only 9 out of 18 children with an adequate ATT/ITT response showed a normal serum GH concentration during the metyrapone test.
- In some cases, peak GH levels occurred at the start of the metyrapone infusion, and timing discrepancies were noted between compound S and GH peak concentrations.
Conclusions:
- The intravenous metyrapone test is not a satisfactory method for assessing GH reserve in children.
- The observed discrepancies challenge the hypothesis that stress-induced GH release is secondary to adrenocorticotrophic hormone release.
Abstract:
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.