The harp seal, Pagophilus groenlandicus (Erxleben, 1777). V. Levels of haemoglobin, iron, certain metabolites and enzymes in the blood

The normal levels of haemoglobin, iron, certain metabolites (glucose, fat, and cholesterol) and enzymes (amylase, aldolase, lactic dehydrogenase, and lipase/esterase) in the blood of the harp seal were estimated. All values except for the lipase (esterase), were considerably higher than those recorded for other animals, including man. The elevated level of lactic dehydrogenase activity as a normal characteristic of the blood is attributed to the role of the enzyme in the oxidation of lactic acid to pyruvate as an adaptation in a diving animal. The extremely low level of lipase (esterase) activity in the blood is suggested to be indicative of the fact that fat is not the favored metabolite for muscular energy in a diving animal.