Abstract

N-Isopropyl methoxamine (IMA) blocks certain metabolic effects of catecholamines in the conscious dog. These include the marked rise in plasma free fatty acids (FFA), blood glucose and blood lactic acid induced by epinephrine and the rise in plasma FFA caused by norepinephrine. Also, IMA inhibits in vitro the catecholamine-induced release of FFA from the rat epididymal fat body and the reactivation of rabbit liver phosphorylase. In vivo and in vitro experiments show that the L-isomer is the active form of the drug in exerting these blocking effects. Like IMA, methoxamine blocks in the conscious dog the rise in plasma FFA, the hyperglycemia caused by epinephrine, and the epinephrine-induced release of FFA from the rat epididymal fat body.