Hepatic Expression of Insulin-Like Growth Factor-1 inUnderfed Pregnant Ewes

摘要

cqvip:The liver is one of the most important visceral organs, which represents a large contribution to whole animal energyexpenditure and the major synthetic site of insulin-like growth factor-I （IGF-1） peptide. Decreased plane of nutrition acts byreducing the metabolic rate and mass of metabolic tissues, such as liver. Also, undernutrition results in the reduced circulating IGF-1concentrations, due to the uncoupled growth hormone-IGF （GH-IGF） axis. This study investigated whether a 22-day period ofundernutrition （half maintenance） could affect liver mass and IGF-1 protein and gene expression. Sixteen pregnant ewes fed all （n =9） or half （n = 7） of their maintenance energy requirements were slaughtered on day 7 of pregnancy （oestrus = day 0）. Body and livermass, IGF-1 plasmatic concentrations and liver IGF-1 mRNA and protein expression were determined. Liver mass and the proportionof liver mass to empty body weight were lower in underfed animals. While IGF-1 plasmatic concentrations were lower inundernourished ewes, no differences in liver mRNA expression were found. This is the first time that differences inimmunohistochemistry intensity and total content are reported in sheep. In summary, the decreased plasma IGF-I concentrationsinduced by undernutrition in ewes was not associated with its reduced hepatic mRNA or protein expression, but to a decrease in livermass.