F. Frick et al., Long-term growth hormone excess induces marked alterations in lipoprotein metabolism in mice, AM J P-ENDO, 281(6), 2001, pp. E1230-E1239
Citations number
62
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
The effects of long-term chronic growth hormone (GH) excess on lipid and li
poprotein metabolism were investigated in 8-mo-old bovine GH (bGH)-transgen
ic mice. Total body weight, serum cholesterol, insulin-like growth factor-I
, and insulin levels were higher, whereas serum levels of glucose, free fat
ty acids, and triglycerides were lower in transgenic mice. Very low-density
lipoprotein (VLDL) cholesterol levels were lower, and low-density lipoprot
ein (LDL) cholesterol levels were higher, in transgenic mice irrespective o
f gender, whereas only transgenic male mice had higher high-density lipopro
tein cholesterol levels. Total serum apolipoprotein B (apoB) levels were no
t affected, but the amount of apoB in the LDL fraction was higher in transg
enic mice. Hepatic LDL receptor expression was unchanged, whereas apoB mRNA
editing and hepatic triglyceride secretion rate were reduced in bGH-transg
enic male mice. Both lipoprotein lipase activity in adipose and heart tissu
e and beta -adrenergic-stimulated lipolysis were increased in transgenic ma
le mice. The relative weight of adipose tissue was lower in transgenic mice
, whereas hepatic triglyceride content was unchanged. Fat feeding of the mi
ce equalized serum triglycerides and free fatty acids in bGH-transgenic and
control mice. In summary, longterm GH excess is associated with marked alt
erations in lipid and lipoprotein metabolism, indicating decreased producti
on and increased degradation of VLDL and preferential flux of fatty acids t
o muscle tissues.