Increases in Tyrosine Hydroxylase Activity after Exposure to Cyclopropane and Fluroxene

Abstract

Prolonged exposure to subanesthetic concentrations of fluroxene and cyclopropane increased adrenal tyrosine hydroxylase activity in citro. In addition, cyclopropane increased the activity of tyrosine hydroxylase in the superior cervical ganglion and that of phenylethanolamine-N-mcthyltransferase in the adrenal. The increase in adrenal tyrosine hydroxylase may be prevented by prior division of the splanchnic nerve fibers which supply the adrenal. The relative increase in cnzyinic activity in vitro is less than the increase in production of radioactive catecholamines from injected “H-tyrosine by the adrenal in vivo. Exposure of rats to 10 per cent cyclopropane for 24 hours produced a significant increase in Pacot, but it is doubtful that the changes in enzymic activity observed after cyclopropane arc the result of hypercarbia.