Pyruvate and Citrate Concentrations in Rabbit Aqueous Humour Determined by an Enzymatic Procedure

Abstract

A modification of Moellering & Gruber's enzymatic-spectrophotometric method (1966) has been employed for determining the pyruvate and citrate concentrations in rabbit aqueous humour. Aqueous humour sqmples from non-fasting, female albino rabbits of Danish country breed, aged from 4 to 36 months, were found to have the following concentrations (mean t s.d.): pyruvate (28 animals): 339 p n o l / l citrate (28 animals): 354 pmol/l & 48 glucose (9 animals): 6.1 mmol/l 0.6, determined with a Beckmann glucose analyzer.The following concentration ratios were found in rabbit aqueous humour: pyruvate/citrate: 0.98 ? 0.18, glucoseipyruvate: 19.2 k 2.2, and glucose/citrate: 17.3 k 2.5. The pyruvatq/citrate ratio was found to decrease with increasing age (0.05 > P > 0.02).Citrate and pyruvate determinations in the same watery pool yielded a day-to-day accuracy of the method expressed by coefficients of variation of 7.6 'O/o for pyruvate and 6.1 O/o for citrate. 50Key words: rabbitaqueous humourglucosepyruvatecitrate. Abbreviations used: NAD+, NADH: oxidized and reduced forms of diphosphopyridine nucleotide (coenzyme I). LDH: lactate dehydrogenase. MDH: malic dehydrogenase. Received June 22, 1973. 14, 116-131. rior chambers of rabbit eye. Arch. Ofihthal. 50, 401-417. Biochem. 17, 369-376. that of plasma and aqueous humours. Arch. Ophthal. 63, 715-720. metabolite levels under various conditions. Ophthal. Res. 3, 241-250.

Glucose, Pyruvate and Citrate Concentrations in the Aqueous Humour of Human Cataractous Eyes

“…The age groups included in the present investigation showed no correlation between age and concentrations of glucose, pyruvate, and citrate, or between age and ratios of glucose aqueoudglucose plasma, glucose aqueous/pyruvate aqueous, pyruvate aqueoudcitrate aqueous, citrate aqueoudcitrate plasma, or glucose aqueous/citrate aqueous. In oxen and rabbits, where a larger proportion of the normal span of life, including part of the growth period, was represented, the pyruvate/citrate ratio was found to decline with increasing age (Bruun Laursen 1972 andBruun Laursen 1973).…”

“…In two previous papers the results are stated of determinations of pyruvate and citrate concentrations in aqueous humour from oxen (Bruun Laursen 1972) and rabbits (Bruun Laursen 1973). In both animal species it was demonstrated that the pyruvate/citrate ratio fell with increasing age.…”