title: The effect of treatment with the oral growth hormone (GH) secretagogue MK-677 on GH isoforms.
abstract: Growth hormone (GH) consists of several isoforms. We have studied the proportion, expressed as percentage of total GH concentration, of non-22kDa (non-22K) GH isoforms and 20K GH during 8-week oral treatment with MK-677 25mg daily in 12 obese males. The proportion of non-22K GH isoforms in peak total GH samples after the initial MK-677 administration was higher than that after 2 and 8 weeks (p<0.01 and p<0.05, respectively). In selected non-peak total GH samples after the initial MK-677 administration, however, the proportion of non-22K GH isoforms was similar to that in the peak total GH samples after 2 and 8 weeks. The proportion of 20K GH in 2-h samples after the initial MK-677 administration was lower than that after 2 and 8 weeks (p<0.01 and p<0.05, respectively). We concluded that the proportion of non-22K GH isoforms was higher in peak, but not in non-peak, total GH samples after the initial MK-677 administration than that observed after multiple doses. The proportion of 20K GH in 2-h samples after the initial MK-677 administration was lower than that after 2 and 8 weeks. These moderate changes in the proportion non-22K GH isoforms are likely of small importance for the clinical response to MK-677 treatment.
authors.affiliation: Research Centre for Endocrinology and Metabolism, Sahlgrenska University Hospital, Gröna Straåket 8, SE-413 45 Göteborg, Sweden. johan.svensson@medic.gu.se
authors.forename: J
authors.initials: J
authors.lastname: Svensson
authors.forename: C L
authors.initials: CL
authors.lastname: Boguszewski
authors.forename: F
authors.initials: F
authors.lastname: Shibata
authors.forename: B
authors.initials: B
authors.lastname: Carlsson
authors.forename: L M S
authors.initials: LM
authors.lastname: Carlsson
authors.forename: B-A
authors.initials: BA
authors.lastname: Bengtsson
mesh_terms: D000284:Administration, Oral; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D004311:Double-Blind Method; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007211:Indoles / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D010446:Peptide Fragments / Q000097:blood*; D020033:Protein Isoforms; D013141:Spiro Compounds / Q000008:administration & dosage*
chemical_list: D007211:Indoles; D010446:Peptide Fragments; D020033:Protein Isoforms; D013141:Spiro Compounds; C404802:human growth hormone 22K; D019382:Human Growth Hormone; C094817:ibutamoren mesylate