In vitro and in vivo inhibitory effect of dehydroepiandrosterone on respiration.

The inhibitory effect of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulphate (DHEA-S) was tested either in vitro with the use of Clark electrode combined with polarography or in vivo using the Spirolyt apparatus. In vitro, DHEA and progesterone showed a marked inhibitory effect on oxygen consumption by the rat heart liver mitochondria. A decrease of oxygen consumption was also observed with electron transporting particles (ETP). However, in both instances DHEA-S was without effect. In vivo, DHEA inhibited whole body oxygen consumption in rats, provided the steroid was injected in a dose of 50 mg kg-1 and 1--16 h before the measurement. No effect was obtained 9 h after DHEA injected in a dose of 5 mg kg-1. Also DHEA administered per os (25 mg kg-1) for six days was without effect as measured 16 h after the last dose. These data are discussed in connection with the beneficial effect of DHEA-S administered to patients with angina pectoris.