Comparison of the effects of growth hormone and insulin-like growth factor I on substrate oxidation and on insulin sensitivity in growth hormone-deficient humans.
AUTOR(ES)
Hussain, M A
RESUMO
Insulin-like growth factor-I (IGF-I) is considered to be the mediator of the growth-promoting effects of growth hormone (GH). The metabolic effects of these two hormones, however, are different. Whereas GH treatment leads to elevated insulin and glucose levels, reduced insulin sensitivity, and impaired glucose tolerance, IGF-I treatment leads to reduced insulin and GH levels and enhanced insulin sensitivity. IGF-I may, therefore, not only be the mediator of the growth-promoting effects of GH but also a modulator of the effects of GH on insulin action and glucose metabolism. To study the influence of GH and IGF-I on substrate metabolism and insulin sensitivity (assessed by euglycemic, hyperinsulinemic clamping combined with indirect calorimetry and glucose tracer infusion), we have treated eight GH-deficient adults with GH (2 IU/m2 daily subcutaneously [s.c.]), IGF-I (10 micrograms/kg.h s.c.), or both hormones together for 7 d, respectively, and compared the effects of these treatment regimens with a control phase. Our findings suggest that (a) both GH and IGF-I promote lipolysis and lipid oxidation, albeit by different mechanisms; (b) treatment with either hormone is followed by enhanced energy expenditure and reduced protein oxidation; and (c) IGF-I reverses the insulin resistance induced by GH.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=295178Documentos Relacionados
- Insulin-like growth factor I stimulates lipid oxidation, reduces protein oxidation, and enhances insulin sensitivity in humans.
- Comparison of the effects of recombinant human insulin-like growth factor-I and insulin on glucose and leucine kinetics in humans.
- Effect of insulin-like growth factor-1 on the responses to and recognition of hypoglycemia in humans. A comparison with insulin.
- Effects of growth hormone and insulin-like growth factor I on rabbit proximal convoluted tubule transport.
- A low dose euglycemic infusion of recombinant human insulin-like growth factor I rapidly suppresses fasting-enhanced pulsatile growth hormone secretion in humans.