Glucose utilization in the horse

Abstract

1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U- 14 C] glucose and [2- 3 H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting, the total entry rate fell from 1·44±0·11 ( n 4) to 1·19±0·12 mg/min per kg body-weight ( P > 0·01) and irreversible loss fell from 1·36±0·10 ( n 4) to 1·05±0·10 mg/min per kg body-weight ( P > 0·02). Recycling rate did not change significantly. 4. In one pony the intravenous infusion of glucose at rates of 0·52, 1·0 or 1·64 mg/min per kg body-weight had no appreciable effect on endogenous glucose production whereas in a second pony, similarly fed, total entry was depressed by 43% and irreversible loss by 54%.5. Irreversible loss of glucose in the horse is similar to that of many other species.