title: Growth hormone isoforms release in response to physiological and pharmacological stimuli.
abstract: Ten healthy subjects used to performing regular physical activity and eight subjects affected by idiopathic isolated GH deficiency (GHD) were enrolled; 22- and 20-kDa GH secretion and its biological activity were evaluated in response to pharmacological stimuli such as arginine, L-dopa or glucagon in GHD children, while the hormonal response to exercise was studied according to Bruce protocol in healthy subjects. We found a significant increase in 22- and 20-kDa GH level in healthy subjects after monitored physical exercise (MPE; basal 0.28+/-0.12 vs 7.37+/-2.08 ng/ml and basal 0.076+/-0.04 vs 0.18+/-0.05 ng/ml, respectively). Furthermore, the 22-kDa/20-kDa ratio significantly increased in children who had undergone MPE and the GH bioactivity basal mean value also increased significantly after exercise (basal 2.86+/-0.76 vs 7.64+/-1.9 ng/ml). The mean value of 22-kDa GH in GHD patients increased significantly following GH pharmacological stimulation (2.78+/-0.63 ng/ml) when compared with mean basal (0.20+/-0.11 ng/ml) value. In the GHD group the basal concentration of 20-kDa GH significantly increased following GH pharmacological stimulation (0.34+/-0.11 vs 0.72+/-0.2 ng/ml); the 22-kDa/20-kDa ratio significantly increased too. Likewise, GH bioactivity in children with GHD increased significantly after pharmacological stimulation test (basal 2.53+/-0.56 vs 7.33+/-1.26 ng/ml). Both GH isoform concentrations and their biological activity are significantly increased in healthy subjects after submaximal exercise protocol and in GHD children after pharmacological stimuli.
authors.affiliation: Department of Pediatric, University of Pavia, 27100 Pavia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Pagani
authors.forename: M
authors.initials: M
authors.lastname: Cappa
authors.forename: C
authors.initials: C
authors.lastname: Meazza
authors.forename: G
authors.initials: G
authors.lastname: Ubertini
authors.forename: P
authors.initials: P
authors.lastname: Travaglino
authors.forename: E
authors.initials: E
authors.lastname: Bozzola
authors.forename: M
authors.initials: M
authors.lastname: Bozzola
mesh_terms: D000293:Adolescent; D002648:Child; D004393:Dwarfism, Pituitary / Q000188:drug therapy / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D004364:Pharmaceutical Preparations / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism
chemical_list: D004364:Pharmaceutical Preparations; D020033:Protein Isoforms; D019382:Human Growth Hormone; D007980:Levodopa; D005934:Glucagon