A PLACEBO-CONTROLLED TRIAL OF INTRANASAL GROWTH HORMONE-RELEASING HORMONE [GHRH(1-44)-NH2] ADMINISTRATION IN NORMAL YOUNG-ADULTS

Growth hormone-releasing hormone, GHRH(l-44), was administered intranasally to 16 healthy young adult male volunteers in a placebo-controlled study using a dose of 1,000 ug dissolved in two different solvent vehicles: water alone and water with the surface tension-lowering agent Tween 80 (0.12%). The growth hormone (GH)-releasing effects of intranasal GHRH as well as that of the vehicle were established and compared to the effects of 80 μg intravenous GHRH. Plasma GH response was assessed by frequent blood sampling over an 180-min period, using both peak response and area under the curve (AUC). The results show that the GH-releasing effects of intranasal GHRH are comparable whichever vehicle is used, and are similar, with the dose of 1,000 μg, to the response obtained following the administration of 80 μg intravenous GHRH. Peak GH responses to GHRH (means ± SEM) were 25.6 ± 4.2 ng/ml (1,000 μg GHRH with water), 32.9 ± 9.1 ng/ml (1,000 μg with water plus Tween 80) and 36.3 ± 7.8 ng/ml (80 μg i.v. administration) (not significant). There was no significant GH response to placebo. Mean peak GH responses occurred after approximately 30 min in all three active treatments (29.2 ± 2.7, 33.9 ± 3.2 and 30.9 ± 3.9 min, respectively). The AUC values (ng-min-ml-1) were not statistically different: 1,914.4 ± 386.7 (water), 2,176.2 ± 599.9 (water plus Tween 80) and 2,419.2 ± 506.9 (i.v.) (not significant). Intranasal GHRH administration was well tolerated in all subjects. Occasional local reactions consisted of a prickly sensation in the nostrils or sneezing irrespective of the vehicle used. Long-term tolerance should be established before considering trial of intranasal GHRH administration in the treatment of GH-deficient children. © 1990 S. Karger AG, Basel.