Simultaneous stimulation of growth hormone, adrenocorticotropin and cortisol with L-dopa/L-carbidopa and propranolol in children of short stature

In 59 otherwise healthy children of short stature, the simultaneous respons e of growth hormone, cortisol and plasma adrenocorticotropin (ACTH) to L-do pa/L-carbidopa and propranolol at 45 and 90 min after administration were i nvestigated. A growth hormone response of 10 mu g/l or higher was considere d positive. The definition of a positive cortisol response included either a hormone increase of at least 193 nmol/l or a peak hormone level of at lea st 497 nmol/l. The ACTH increase had to be fourfold above 11 pmol/l to be c onsidered positive. In the 59 investigated children, the median basal growt h hormone levels increased from 1.35 mu g/l to 18.05 mu g/l and 10.15 mu g/ l at 45 and 90 min after stimulation (p <0.05). The median cortisol levels rose from 242 nmol/l to 439 nmol/l and 612 pmol/l, and the corresponding me dian ACTH levels from 2.94 pmol/l to 9.63 pmol/l and 11.13 pmol/l at 45 and 90 min after stimulation. Significant positive hormone response rates were 88.1% for growth hormone, 88.1%, for cortisol and 69% for ACTH. These resu lts could be attributed to the enhanced stimulating effect of the additiona l administration of L-carbidopa and propranolol. We conclude that the administration of L-dopa/L-carbidopa and propranolol i s useful for the simultaneous evaluation of growth hormone, cortisol and AC TH secretion in children of short stature.