Apomorphine does not decrease tissue levels of tetrahydrobiopterin in vivo.
It was reported that R(-)apomorphine and other catechols are potent inhibitors of dihydropteridine reductase in vitro. It was suggested that decreased levels of tetrahydrobiopterin may represent a mechanism by which R(-)apomorphine inhibits catecholamine synthesis in vivo. This paper demonstrates that tetrahydrobiopterin levels are not affected either in vitro (PC12 cells) or in vivo (rat liver and corpus striatum) by treatment with R(-)apomorphine, whereas DOPA (3,4-dihydroxyphenylalanine) production (PC12 cells, corpus striatum) is reduced. This indicates that R(-)apomorphine does not inhibit DOPA production by reducing 6(R)-L-erythro-tetrahydrobiopterin) levels.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001708:Biopterins / Q000031:analogs & derivatives* / Q000378:metabolism; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000096:biosynthesis; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008727:Methotrexate / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D001708:Biopterins; D004295:Dihydroxyphenylalanine; C003402:sapropterin; D001058:Apomorphine; D008727:Methotrexate