title: Serum levels of 20 kilodalton human growth hormone (20K-hGH) in patients with acromegaly before and after treatment with octreotide and transsphenoidal surgery.
abstract: Circulating human GH (hGH) consists of several molecular isoforms. It was previously reported that the proportion of 20 kilodalton hGH (20K-hGH) was elevated in the serum of patients with active acromegaly. In this study, we investigated the effects of octreotide and transsphenoidal adenomectomy on the proportion of 20K-hGH in the serum of 7 acromegalic patients. To achieve an acute effect, octreotide (100 microg) was subcutaneously injected as a bolus. To observe the chronic effects of octreotide therapy and surgery, serum samples were obtained by repetitive blood sampling before and 3 to 8 weeks after treatment. Serum levels of 20K-hGH and 22 kilodalton hGH (22K-hGH) were determined by specific enzyme-linked immunosorbent assay. A bolus injection of octreotide elicited a parallel decrease in serum 22K-hGH and 20K-hGH, resulting in an unchanged proportion of 20K-hGH to total circulating hGH. The proportion of 20K-hGH was decreased in 4 of 4 patients 4 to 7 weeks after surgery and in 2 of 4 patients after chronic treatment with octreotide for 3 to 8 weeks. The proportion of serum 20K-hGH was positively related to mean serum 20K-hGH as well as serum total hGH levels, but not with serum IGF-I levels. These findings suggest that high serum levels of 20K-hGH or total hGH per se might elicit a chronic change in the clearance kinetics of 20K-hGH and increase the proportion of 20K-hGH in acromegalic patients.
authors.affiliation: Department of Endocrinology, Metabolism and Hematological Oncology, School of Medicine, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Murakami
authors.forename: Tadashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000172:Acromegaly / Q000097:blood* / Q000188:drug therapy / Q000601:surgery*; D000328:Adult; D000368:Aged; D005260:Female; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D015282:Octreotide / Q000627:therapeutic use*; D020033:Protein Isoforms / Q000097:blood
chemical_list: D020033:Protein Isoforms; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D015282:Octreotide