Serum activation of lipoprotein lipase from sheep adipose tissue

The effects of species and plane of nutrition on serum activation of sheep adipose tissue lipoprotein lipase were studied over a range of substrate (triolein) concentrations. Serum, either from two species or from the same species on a different plane of nutrition, had differing effects on adipose tissue lipoprotein lipase activity. Serum from fed sheep was more effective than serum from fed rats in activating sheep adipose tissue lipoprotein lipase at low substrate concentrations. Serum taken from sheep on a restricted plane of nutrition, stimulated adipose tissue lipoprotein lipase activity at physiological substrate concentrations. The increased activity promoted by the factor(s) present in serum would ensure that those tissues (e.g. cardiac and skeletal muscle) which continue to synthesize lipoprotein lipase during fasting or nutritional restriction, are able to assimilate the relatively low amounts of circulating triacylglycerol.