Abstract
Effects of norepinephrine infusion on rectal temperature, plasma FFA concentration and its turnover rate were studied in intact and functionally eviscerated rats.
Norepinephrine infusion caused a greater increase in the rectal temperature, and less elevation in plasma FFA concentration in cold-acclimated rats in comparison with the changes in warm-adapted control rats.
Norepinephrine infusion also brought about a significant increase in the turnover rate of plasma FFA in both groups of rats. The regression coefficient of plasma FFA turnover rate versus FFA concentration was greater in cold-acclimated group than in the controls. It was assumed that peripheral capacities of FFA uptake were greater in cold-acclimated rats than in the controls.
The thermogenic effect of norepinephrine in eviscerated rats did not differ from that in non-eviscerated rats. The infusion caused an increase in the rectal temperature in eviscerated cold-acclimated rats, but not in warm-adapted ones. Norepinephrine infusion produced a similar marked elevation in plasma FFA concentration in both eviscerated coldacclimated and warm-adapted rats, while increase in FFA turnover rate was much greater in the former group than in the latter. The regression coefficient of plasma FFA turnover rate on its concentration was greater in eviscerated cold-acclimated rats than in the controls.
