scholarly journals Diagnosis of growth hormone deficiency in adults by testing with GHRP-6 alone or in combination with GHRH: comparison with the insulin tolerance test

2002 ◽  
pp. 667-672 ◽  
Author(s):  
S Petersenn ◽  
R Jung ◽  
FU Beil

OBJECTIVE: The diagnosis of GH deficiency in adults should be made using provocative testing of GH secretion. The insulin tolerance test (ITT) is recommended as the gold standard investigation. Because of the risk of serious complications, patients with epilepsy or known ischemic heart disease should not undergo this test. GHRP-6 is a synthetic hexapeptide that releases GH by binding to specific hypothalamic and pituitary receptors. We assessed the diagnostic capability of GH stimulation by GHRP-6 alone or in combination with GHRH in comparison to the results of an ITT. DESIGN: Twenty patients underwent an ITT for suspected pituitary or adrenal disease. Either GHRP-6 (1 microg/kg) alone, or GHRP-6 in combination with GHRH (1 microg/kg) were administered on different days. Blood samples were obtained during a subsequent 90-min period for measurement of GH. RESULTS: Ten patients had a GH peak response of less than 3 microg/l during ITT and were considered growth hormone deficient (GHD). The GH mean peak (+/-S.E.M., range) in this group was 0.7 microg/l (+/-0.3, 0.1-2.9) compared with 14.5 microg/l (+/-3.5, 3.8-40.8) in the group of patients with a GH peak response of more than 3 microg/l (growth hormone sufficient (GS)). For the GHRP-6 test, the GH mean peak was 1.3 microg/l (+/-0.6, 0.1-6.7) in the GHD group versus 25.7 microg/l (+/-5.5, 7.7-54.2) in the GS group. After GHRP-6+GHRH, the GH mean peaks were 4.0 microg/l (+/-1.3, 0.2-11.9) versus 54.7 microg/l (+/-11.1, 13.9-136.0) respectively. During administration of GHRP-6, the only side effects observed were flush symptoms. CONCLUSIONS: Peak GH levels below 7 microg/l for the GHRP-6 test and below 13 microg/l for the combined GHRP-6+GHRH test identified all patients with GH deficiency correctly as defined by ITT. The results suggest that testing with GHRP-6 or GHRP-6+GHRH is as sensitive and specific as an ITT for the diagnosis of adult GH deficiency.

1989 ◽  
Vol 122 (1) ◽  
pp. 61-68 ◽  
Author(s):  
L. Gelander ◽  
K. Albertsson-Wikland

ABSTRACT Endogenous GH secretion was measured every 20 min for 24 h in 36 short children. This was immediately followed by an i.v. injection of GH-releasing hormone (GHRH)(1–29)-NH2 (1 μg/kg), and GH was estimated every 15 min for the following 2 h. The aim was to determine whether endogenous pulsatile GH secretion had any relation to, or influence on, the GH release induced by GHRH. A high variability was found both in the 24-h GH secretion expressed as area under the curve above the baseline (0–1588 mU/l × 24 h) and the maximal GH response to GHRH (5–296 mU/l), as well as after an arginine–insulin tolerance test (4–59 mU/l). We found a positive correlation (correlation coefficient of Spearman (rs) = 0·49; P < 0·01) between the GH response to GHRH and the spontaneous GH secretion over a 24-h period, in spite of a negative correlation (rs = −0·80; P < 0·01) with the GH secretion during the preceeding 3 h. We conclude that the GH response to a GHRH test correlates with endogenous GH secretion in short children, and may be helpful in estimating the ability to release GH. It is important, however, to be aware of the influence of the spontaneous GH secretion during the 3 h immediately preceeding administration of GHRH. Journal of Endocrinology (1989) 122, 61–68


1995 ◽  
Vol 133 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Hans C Hoeck ◽  
Peter Vestergaard ◽  
Poul E Jakobsen ◽  
Peter Laurberg

Hoeck HC, Vestergaard P, Jakobsen PE, Laurberg P, Test of growth hormone secretion in adults: poor reproducibility of the insulin tolerance test. Eur J Endocrinol 1995;133:305–12. ISSN 0804–4643 The insulin tolerance test (ITT) is regarded as the most reliable provocative test in the diagnosis of growth hormone (GH) deficiency in adults. In the present study the test was evaluated by investigating the range of GH responses in normal adult males and females and the intra-individual reproducibility of the test. Sixteen healthy non-obese adults, eight males (median age 31.5 years) and eight females (median age 31.8 years) were tested twice with the ITT, with a minimum of 72 h between each test. The females were tested between day 3 and day 10 of their menstrual cycles. Adequate hypoglycemia was achieved in all cases with a median nadir blood glucose of 1.3 mmol/l (range 0.8–2.0). Growth hormone in serum was measured by immunoradiometric assay and low values were confirmed by a different assay. Median peak GH concentration responses to the ITT were: in males 27.9 μg/l, range 5.0–71.1 (test 1) and 30.5 μg/l, range 7.9–69.5 (test 2); and in females 9.0 μg/l, range 4.1–17.9 (test 1) and 8.4 μg/l, range 0.09–42.4 (test 2). The rise in GH concentration during the ITT was higher in males than in females. In the males, all stimulated GH values were ≥5.0 μg/l. In the females, four out of 16 tests gave values below 5.0 μg/l and in one test the GH value was around the detection limit of the assays. There was poor reproducibility during repeated testing, with no correlation between the results of the two tests. The results did not correlate to the magnitude of the hypoglycemia. The results of this study illustrate the complexity of the regulation of GH secretion and indicate that the ITT is less useful for diagnosing GH deficiency in adults than previously anticipated. The diagnosis of GH deficiency in adults and especially in adult females should not be based on the results of a single ITT alone. Hans C Hoeck, Department of Endocrinology, Aalborg Regional Hospital, Reberbansgade, DK-9000 Aalborg, Denmark


2021 ◽  
Vol 71 (1) ◽  
pp. 184-89
Author(s):  
Nida Basharat Khan ◽  
Asif Ali Memon ◽  
Sumbal Nida ◽  
Naveed Asif ◽  
Saima Shakeel Malik ◽  
...  

Objective: To introduce a relatively convenient and effective way of conducting Insulin Tolerance Test for diagnosis of Growth Hormone deficiency in children with short stature. Study Design: Cross sectional analytical study. Place and Duration of Study: Conducted at Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from May 2017 to Jul 2018. Methodology: A total of 185 cases were included. Sample selection was done by non-probability consecutive sampling technique. Insulin tolerance test was performed by taking basal sample for serum growth hormone and plasma glucose levels before giving intravenous insulin bolus according to dose of 0.15 IU/kg. Samples for Growth Hormone level were repeated at time of induced hypoglycemia (defined as plasma glucose level of <2.8 mmol/L), 30 minutes and 60 minutes post induction. Results: Mean age of the patients was 10 ± 4 years, majority 120 (65%) were males. In the study population, 41 (22%) patients showed adequate response to insulin tolerance test while 144 (78%) showed inadequate response. At level of induction, mean growth hormone levels were 31.9 ± 18.8 mIU/l and 4.7 ± 4.4 mIU/l in patients showing adequate and inadequate response respectively (p-value <0.05). Majority 32 (78%) of the patients showing adequate response had peak growth hormone response (>20 mIU/l) at induction alone, followed by 30 minutes post induction; reflecting the significance of these two samples in diagnosis of growth hormone deficiency. Conclusion: We concluded that there is a simpler ...........


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