title: Octreotide, but not bromocriptine, increases circulating insulin-like growth factor binding protein 1 levels in acromegaly.
abstract: Twenty-three patients with active acromegaly underwent serum sampling for growth hormone (GH), insulin and insulin-like growth factor binding protein 1 (IGFBP-1) after placebo or single doses of octreotide or bromocriptine. Integrated 24-h serum GH levels decreased by 90% after octreotide and 49% after bromocriptine. A statistically significant correlation between the course of GH levels after octreotide and bromocriptine was observed (p < 0.001). Octreotide, but not bromocriptine, induced a significant increase in integrated 24-h serum IGFBP-1 levels to 37.4 times the baseline values. Bromocriptine caused a non-significant increase in integrated 24-h serum IGFBP-1 levels, which argues against a direct regulatory effect of GH on IGFBP-1 production in acromegaly. In conclusion, octreotide induces in acromegaly the production of IGFBP-1, which occurs independently of the number of somatostatin receptors on the GH-secreting pituitary adenoma. The supposed inhibitory effect of IGFBP-1 on the biological effect of IGF-1 might result in an additional clinical benefit in acromegalic patients as compared to treatment directed at the pituitary level.
authors.affiliation: Department of Internal Medicine III, Erasmus University, Rotterdam, The Netherlands.
authors.forename: W W
authors.initials: WW
authors.lastname: de Herder
authors.forename: P
authors.initials: P
authors.lastname: Uitterlinden
authors.forename: A J
authors.initials: AJ
authors.lastname: van der Lely
authors.forename: L J
authors.initials: LJ
authors.lastname: Hofland
authors.forename: S W
authors.initials: SW
authors.lastname: Lamberts
mesh_terms: D000172:Acromegaly / Q000097:blood* / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D001971:Bromocriptine / Q000627:therapeutic use*; D002352:Carrier Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use*; D013002:Somatomedins / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D013002:Somatomedins; D001971:Bromocriptine; D015282:Octreotide