Biochemical changes in liver and blood during liver fattening in rats.

Excessive fat accumulation in the liver is a common metabolic disorder seen in humans and animals. Fatty liver was induced in the rat by feeding the animals with a sucrose rich diet containing 1% orotic acid for 2-3 weeks. In the sera from fatty liver rats there were significant changes in the level of alanine aminotransferase (+ 68.7%), malic dehydrogenase (+ 77.8%), gamma-glutamyl transpeptidase (- 53.4%) and total lipids (+ 26.6%). There were small to no changes in the levels of aspartate aminotransferase, glucose-6-phosphate dehydrogenase, lactic dehydrogenase, aldolase, malic enzyme, 6-phosphogluconic acid dehydrogenase, alkaline phosphatase and albumin. In fatty liver, significant differences were seen in the levels of glucose 6-phosphate dehydrogenase (+ 235%), malic enzyme (+ 170%), gamma-glutamyl transpeptidase (+ 113%), 6-phosphogluconate dehydrogenase (+ 63%), aspartate aminotransferase (+ 35.6%), malic dehydrogenase (+ 38%), lactic dehydrogenase (+ 37%), and alanine aminotransferase (- 23%). Comparison of the non-fatty part with the fatty part of the fatty liver showed larger changes in the non-fatty part of the liver, suggesting that during the fattening process, there is an induction of enzymes in the liver reaching a peak prior to lipid accumulation, declining thereafter during liver fattening. The increase in NADPH-generating lipogenic enzymes suggests that accumulated fat in the liver is at least partially from de-novo increased synthesis in the liver.