Regulation of binding proteins for insulin-like growth factors (IGF) in humans. Increased expression of IGF binding protein 2 during IGF I treatment of healthy adults and in patients with extrapancreatic tumor hypoglycemia.
J Clin Invest
; 86(3): 952-61, 1990 Sep.
Article
em En
| MEDLINE
| ID: mdl-1697608
ABSTRACT
UNLABELLED Insulin-like growth factors (IGFs) in blood form two complexes with specific binding proteins (BPs) a large, growth hormone (GH)-dependent complex with restricted capillary permeability, and a smaller complex, inversely related to GH, with high turnover of its IGF pool and free capillary permeability. The distribution of BPs and of IGFs I and II between these complexes was studied in sera from healthy adults treated with IGF I or/and GH and from patients with extrapancreatic tumor hypoglycemia. Like GH, IGF I administration raises IGF I and two glycosylation variants of IGFBP-3 in the large complex, but unlike GH drastically reduces IGF II. During IGF I infusion, IGFBP-3 appears in the small complex whose IGFBP-2 and IGF I increase three- to fivefold and fivefold, respectively. GH treatment, associated with elevated insulin levels, suppresses IGFBP-2 and inhibits its increase owing to infused IGF I. The small complex of tumor sera contains increased amounts of IGFBP-2 and -3, and two- to threefold elevated IGF II. CONCLUSIONS:
low GH and/or insulin during IGF I infusion and in extrapancreatic tumor hypoglycemia enhance expression of IGFBP-2 and favor partition of IGFBP-3 into the small complex. Free capillary passage and high turnover of its increased IGF I or II pools may contribute to compensate for suppressed insulin secretion during IGF I infusion or to development of tumor hypoglycemia.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Somatomedinas
/
Fator de Crescimento Insulin-Like I
/
Fator de Crescimento Insulin-Like II
/
Proteínas de Transporte
/
Hipoglicemia
/
Neoplasias
Limite:
Humans
Idioma:
En
Revista:
J Clin Invest
Ano de publicação:
1990
Tipo de documento:
Article