Norephedrine (phenylpropanolamine) stimulates oxygen consumption and lactate production in the perfused rat hindlimb.
d,l-Norephedrine (phenylpropanolamine) which is both a demethylated analogue and a metabolite of d,l-ephedrine, is a reputed anorectic agent. In the present study the proposed most active isomer of this mixture, l-norephedrine has been assessed as a peripherally acting thermogenic agent in the isolated perfused rat hindlimb. l-Norephedrine produced a dose-dependent increase in oxygen uptake and perfusion pressure and increased lactate production. Whereas propranolol potentiated the increase in oxygen uptake and perfusion pressure produced by l-norephedrine, prazosin significantly and nitroprusside totally inhibited both of these changes. Nitroprusside also completely inhibited the increase in lactate production. We conclude that norephedrine has a hitherto unrecognized peripheral thermogenic activity in the perfused rat hindlimb resulting from its interaction with alpha 1 adrenergic receptors that control vasoconstriction in this tissue.
Hettiarachchi
M
M
Department of Biochemistry, University of Tasmania, Hobart, Australia.
Colquhoun
E Q
EQ
Ye
J M
JM
Rattigan
S
S
Clark
M G
MG
D000818:Animals; D006614:Hindlimb; D007773:Lactates / Q000096:biosynthesis*; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D010477:Perfusion; D010665:Phenylpropanolamine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D007773:Lactates; D010665:Phenylpropanolamine