Atropine: effects on glucose metabolism.

We have employed the primed constant infusion technique to investigate the metabolic effects of the organophosphate antidote, atropine, on glucose homeostasis in rats. This method utilizes the radioisotopes 6-3H-glucose to measure production and uptake and U-14C-glucose to measure oxidation. Our data indicate that glucose production significantly (p less than 0.05) increased (24.0 +/- 2.0 vs. 30.9 +/- 2.6 mumoles.kg-1.min-1) following atropine administration. The elevated rate of glucose turnover was associated with concomitant increases in glucose oxidation (8.3 +/- 0.6 vs. 12.0 +/- 0.8, mumoles.kg-1.min-1), the percent of glucose uptake oxidized (37.2 +/- 2.0 vs. 44.6 +/- 2.6), and the percent carbon dioxide produced from glucose (8.4 +/- 0.7 vs. 12.0 +/- 1.8). Presumably, these glucokinetic changes were mediated by elevated plasma catecholamines (Epi: 166 +/- 19 vs. 271 +/- 50 pg/ml; Norepi: 262 +/- 24 vs. 525 +/- 63 pg/ml, p less than 0.05) since other glucoregulatory hormones (insulin, glucagon, and corticosterone) were not significantly affected by atropine administration. In addition, there was no change in VO2 associated with atropine administration. These data indicate that atropine enhances glucose production and utilization; such effects could be ergogenic during exercise in thermoneutral conditions.