Many of the anabolic effects of growth hormone (GH), including promotion of lean tissue growth, are mediated by the actions of insulin-like growth factor-1 (IGF-1) (Gluckman et al, 1987). It is known that the response of hepatic IGF-1 synthesis to GH may be modulated by alterations in levels of feeding or changes in protein supply (Pell et al, 1993). The aim of the current study was to develop an in vitro model to characterise interactions between amino acid supply and GH on hepatic IGF-1 release in ruminants.
Ovine hepatocyes were prepared by a modification of a published method (Luo et al, 1992) from the median lobe of livers removed immediately after slaughter from sheep killed at a local abattoir. Free amino acid concentrations in test media were 5x, 1x and 0.2x physiological concentrations based upon in vivo ovine portal venous blood data (Lobley et al, 1995).