Effects of dihydroergotamine in athyroid and thyroxinized rats

¹ Division of Physiology, Department of Biological Sciences, Florida State University, Tallahassee, Florida

Athyroid and athyroid-thyroxinized rats showed an increase in oxygen consumption that was linear with the log of the dose of thyroxine. Epinephrine elevated the level of O₂ consumption, but the response was still linear with respect to the log of the thyroxine dose. Dihydroergotamine had a slight depressant effect on the O₂ consumption of all groups, but did not affect the linearity of response. Epinephrine plus dihydroergotamine caused a response similar to that seen when no drugs were administered. The effects of the various treatments on blood sugar levels were exactly parallel to those obtained with O₂ consumption measurements. The data do not support the concept that the action of thyroxine on tissues of the organism is mediated via epinephrine.