Pasteur effect in vascular and intestinal smooth muscle.

The increase in lactate production on changing from aerobic to anaerobic conditions, i.e. the Pasteur effect, has been reported to be small in vascular muscle and especially in aorta. It has been suggested that this may be an artefact caused by damage to the intimal endothelium. We have compared the Pasteur effect in different kinds of pig arteries, but also in rabbit colon. The aerobic lactate production in 60 min was 11-15 mumol/g in the aorta and the carotid artery, but 3 mumol/g in the mesenteric and renal arteries and 4 mumol/g in the rabbit colon. The increase in lactate production under anaerobic conditions was 12-20 mumol/g/60 min in the carotid artery, aorta and rabbit colon and 10 mumol/g/60 min in the mesenteric and renal arteries. When calculated in per cent, the Pasteur effect was greater in the mesenteric artery than in the aorta, but the actual rise in lactate production in mumol/g was higher in the aorta and carotid artery. The high aerobic lactate production of smooth muscle in vitro may be related to its low ability to oxidize glucose; some other substrates may be preferentially oxidized when present in vitro or in vivo.