LIPOPROTEIN-LIPASE IN DEVELOPING RAT-TISSUE - DIFFERENCES BETWEEN WISTAR AND SPRAGUE-DAWLEY RATS

Lipoprotein lipase in animal tissues is known to be affected by fastin g, but contradictory results have been published concerning this effec t in particular tissues. For example, we reported that lipoprotein lip ase activity expressed in the liver of neonatal rats was either increa sed or not affected by fasting. To evaluate the influence of the rat s train used as experimental animal model, we studied differences betwee n Wistar and Sprague-Dawley rats in the development and in the effect of fasting on lipoprotein lipase and hepatic lipase activities in tiss ues of neonatal rats. Beside some minor differences in the development of lipoprotein lipase in some tissues like brown adipose tissue and l ungs, we found quite remarkable differences between both strains in th e development of lipoprotein lipase and hepatic lipase activities in t he liver. In 1-day-old neonates, differences between both strains were also observed in the effect of fasting on lipoprotein lipase activity both in liver and lungs. In the liver of Wistar pups lipoprotein lipa se activity was increased by fasting by 350%, but only by 50% in the l iver of Sprague-Dawley pups. In contrast, in the lungs of Wistar pups lipoprotein lipase activity was increased by fasting by 280%, but by 5 80% in lungs of Sprague-Dawley rats. Therefore, our results indicate t hat quantitative differences exist between Wistar and Sprague-Dawley r ats in the regulation of lipoprotein lipase.