ENZYME ACTIVITIES AND PROTEIN CONCENTRATION IN THE INTRAOCULAR FLUIDS OF TEN MAMMALS

Abstract

An attempt was made to establish normal values for the total protein concentrations and the enzyme activities of LDH [lactate dehydrogenase], MDH [malate dehydrogenase] and PGI [phosphoglucose isomerase] in the intraocular fluids of rats, guinea pigs, rabbits, cats, dogs, sheep, cattle, pigs, horses and humans. Remarkably little species differences were noted in 9 of the 10 mammals with vitreal enzyme activities falling into a narrow range beween 8.4 U/l (PGI, horse) and 92.4 U/l (MDH, guinea pig). All species obeyed the sequence aqueous < vitreous < serum with the exception of the rat, where vitreous activities surpassed serum at least 2-fold. The very low enzyme activities in the aqueous and vitreous humors demand special precautions against contaminations which can either derive from postmortem storage or inadequate sampling procedures. Conversely, elevated enzyme activities could be used as probes for pathological processes or as a check for a clean preparation.