Metabolite and enzyme contents of freeze-clamped liver of the marine fish Stenotomus chrysops.
Hepatic metabolites and enzymes in the marine fish, scup or porgy (Stenotomus chrysops), were determined in freeze-clamped tissue taken either within a day of removing fish from their natural habitat or after scup were held in captivity for 6-8 months. The same determinations were made for liver from fed or 48 hr-starved rats (Mus norvegicus albinus). Compared with rat liver, both groups of fish had, per gram of liver, higher contents of AMP, inorganic phosphate, glucose, glucose-6-phosphate, malate, glutamate and NH4+. ATP was lower in fish liver, and ADP, lactate and pyruvate contents were similar in rats and fish. Fish held in captivity had significantly lower pyruvate, alpha-ketoglutarate, and cytosolic free NAD+/NADH and higher cytosolic free NADPH/NADP+. These decreases were similar to those seen when starved rats were compared with fed ones. In scup liver, glucose-6-phosphate dehydrogenase was 3-8 times, malic enzyme about 2 times, and alanine aminotransferase 2-4 times higher than those activities in rat liver. Those results and a higher cytosolic free NADPH/NADP+ are consistent with the liver being the major site of lipogenesis in fish.
D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D004798:Enzymes / Q000378:metabolism; D005615:Freezing; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D010473:Perciformes / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity
D000227:Adenine Nucleotides; D004798:Enzymes