The Effect of Heat, Cold, and Exercise on Plasma Dopamine-β-Hydroxylase Activity in Man

Publisher Website
Google Scholar
Abstract
The effect of a standardized exercise procedure on plasma dopamine-β-hydroxylase (DBH) activity has been assessed in five normal human subjects. The activity of the enzyme was measured using a sensitive, nonradioactive assay based on the conversion of tyramine to octopamine. Each subject was tested at an ambient temperature of 40 °C and on a subsequent day at a temperature of 10 °C. The resting levels of DBH activity were significantly higher in the cold. A small increase in enzyme activity occurred with exercise at 40 °C, but there was no change in this parameter with exercise in the cold. It is suggested that the rise in plasma DBH activity seen in the cold and with exercise results from increased sympathetic activity. However, the failure of DBH activity to increase with exercise in the cold is poorly understood.

This publication has 0 references indexed in Scilit: