Testing with growth hormone-releasing factor (GRF(1–29)NH2) and somatomedin C measurements for the evaluation of growth hormone deficiency

Abstract

Growth hormone (GH) responses to GRF (1 microgram/kg BW i.v.) were investigated. Comparison between GRF(1-40) and GRF(1-29)NH2 in 11 young adult volunteers gave identical results. One hundred and thirty-one children and adolescents (45 with idiopathic GHD) were tested with GRF (1-29)NH2. The maximal GH levels (max GH) in response to GRF during the 120 min test period were found suitable to characterize the response. In cases without GHD no correlation to age, sex and pubertal development was observed. A maximal GH level of above 10 ng/ml was found to be normal. In 3 out of 86 children without GHD (one with Turner syndrome; two with simple obesity) max GH fell short of 10 ng/ml, while 11 of 45 cases with GHD exceeded this margin. In GHD, max GH was inversely correlated with age. There was no difference in max GH between groups with or without perinatal pathology as a presumed cause of GHD. GH levels to GRF were positively correlated with maximal GH level during sleep in GHD, but not correlated with responses seen to insulin or arginine. The value of GRF testing for the confirmation of GHD is discussed in the light of other GH stimulatory tests and basal somatomedin C measurements. It is suggested that the combination of testing with GRF and the determination of a basal SmC level offers a safe and convenient way to diagnose GHD in clinically suspected cases, though in some cases further diagnostic tests may be needed.

Evaluation of the Growth-Hormone-Releasing Hormone Test in Short Normal and Growth-Hormone-Deficient Children

“…Furthermore, we confirm the lack of correlations be tween GH peaks during conventional tests and GHRH test [13],…”

“…There are inconsistent reports on the duration of endogenous GHRH deficiency to negatively affect GH release [3,4,12,13,16, 20]; we were not able to find any negative correlations between chronological and bone age with GH peaks and integrated values.…”

“…Our study was performed with the well-known GHRH( 1 -44)NH2 form, and with the GHRH(1-29)NH2 fragment, to date used only in small and heterogeneous groups of GH-deficient children [8,9,11,13].…”

Przydatność testu GHRH w diagnostyce niedoboru hormonu wzrostu u dzieci

“…In the case of prolonged inactivity of the hypothalamus and lack of pituitary gland stimulation, the GHRH test can give false positive results. Some authors advocate the use of priming with GHRH for a week prior to the test with GHRH, if damage to the hypothalamus is suspected [13].…”

Rapid effect of intravenous growth hormone (GH)-releasing hormone 1?44 on plasma GH levels in children

“…Before and after administration of GHRH~_44 (1 ~tg/ kg body weight i.v.) blood samples for growth hormone (GH) determination were drawn at -30, 0, 1, 2, 3,4,6,8, 10, 15, 30, 45, 60, and 90 rain. Plasma GH increase was apparent 1rain after injection and in 12 patients (7 female) peak plasma GH values were reached within 15 rain.…”