Some observations on the use of D-glucose-2-3H as a tracer in turnover studies in merino sheep

Abstract

Bolus injection of a mixture of D-glucose-2-3H and -(U)-14C into each sheep enabled a turnover rate to be calculated for each isotope and to be compared in the same animal. No statistically significant differences were found in pool size, or glucose space. The total entry rates calculated from the D-glucose-2-3H results were found to be significantly higher (P is greater than 0,95 paired t test) than those calculated from the D-glucose -(U)-14C results, the average difference being 18%. This difference indicated that the extent of glucose recycling was somewhat less than that reported for monogastric mammals (30%--Katz & Dunn, 1967) and similar to that found by Judson & Leng (1972) in sheep. Glycogen was isolated from skeletal, cardiac and smooth muscle as well as from the liver and the 3H:14C ratios determined. These ratios were found to be significantly higher than those reported for monogastric mammals such as the rat or dog.