Influence of some uremic toxins on oxygen consumption of rats in vivo and in vitro.

According to our present knowledge hypometabolism and hypothermia in uremia are most probably due to direct actions of toxic substances at the cellular level. A cardiovascular etiology seems less possible. A similar reduction of oxygen consumption as observed in uremia can be produced by 5 mg/kg body wt. indole i.p. Acetoine, m- and p-cresol, methylguanidine and putrescine do not reduce oxygen consumption even at tenfold higher doses. Some combinations of these substances, however, are effective when given only 10 mg/kg body wt. each. The effects in vivo cannot be reproduced by employing in vitro systems.