GH and IGF-I binding sites in adipose tissue, liver, skeletal muscle and ovaries of feed-restricted gilts

Abstract

-The influence of feed restriction on GH and IGF-I binding was examined in the cyclic gilt. IGF-I, IGFBPs, insulin and leptin levels in plasma were also measured. Twenty-four gilts whose oestrous cycle was synchronised were used. From day 3 to day 12, (with day 0 being the first day of oestrus) feed allowance was 240% and 80% of the energy requirements for maintenance for well-fed (H) and restricted gilts (L) respectively. Six gilts in each group were treated with an antagonist of GnRH but the treatment had no effect on any reported measurements. Blood and tissue samples were collected on days 12 and 13 respectively. L gilts lost live weight whereas H gilts gained weight. Plasma IGF-I, insulin and leptin concentrations were lower in L than in H gilts whereas plasma IGFBP levels were not affected by feed restriction. The specific binding of 125 I-bGH to adipose tissue, liver, skeletal muscle and ovary membranes did not differ significantly between H and L gilts. Specific binding of 125 I-IGF-I to hepatic membranes was higher in L than in H gilts whereas it did not differ between the two groups in the other tissue membranes.

Influence of feed intake during pregnancy and lactation on fat body reserve mobilisation, plasma leptin and reproductive function of primiparous lactating sows

“…However, contrary to Estienne et al [9], a high correlation was also maintained at day 25 of lactation in our sows. It should be noted that postprandial leptin may increase with feed intake [21,23]. Therefore, body fat reserves may have a negative influence on concentrations of plasma leptin through inhibition of appetite.…”

Childhood obesity and insulin resistance in a Yucatan mini-piglet model: putative roles of IGF-1 and muscle PPARs in adipose tissue activity and development

“…The liver provides the majority of circulating IGF-1 but muscle and adipose tissues also contribute to IGF-1 serum levels. 20 Besides promoting growth, IGF-1 also displays a wide range of metabolic effects that mimic insulin in glucose and lipid metabolism. 21 The precise role of IGF-1 in insulin sensitivity and obesity is still unclear.…”

Leptin and leptin receptor expression in skeletal muscle and adipose tissue in response to in vivo porcine somatotropin treatment1,2

“…In the present study, feed restriction was used to specifically exclude any differences in feed intake caused by pST treatment as contributing to changes in leptin or Ob-Rb mRNA abundance. Feed withdrawal has been demonstrated to decrease leptin mRNA abundance in swine (Spurlock et al, 1998;Salfen et al, 2003), whereas feed restriction to 80% of ME intake decreased serum leptin concentrations by approximately 37% in gilts (Louveau et al, 2000). Thus, exclusion of feed intake as a component of the pST response would permit examination of the data in terms of a specific response to the pST treatment.…”