Effect of adenosine and inosine on ureagenesis in hepatocytes.
Adenosine and inosine produced a dose-dependent stimulation of ureagenesis in isolated rat hepatocytes. Hypoxanthine, xanthine and uric acid were without effect. Half-maximally effective concentrations were 0.08 microM for adenosine and 5 microM for inosine. Activation of ureagenesis by both nucleosides had the following characteristics: (a) it was observed with either glutamine or (NH4)2CO3, provided that glucose was present; (b) it was not detected when glucose was replaced by lactate plus oleate; (c) it was mutually antagonized by glucagon, but not by adrenaline; and (d) it was dependent on Ca2+. We suggest that the action of adenosine and inosine on ureagenesis might be of physiological significance.
Guinzberg
R
R
Departmento de Bioquimica, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, D.F.
Laguna
I
I
Zentella
A
A
Guzman
R
R
Piña
E
E
D000241:Adenosine / Q000494:pharmacology*; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D066298:In Vitro Techniques; D007288:Inosine / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D014508:Urea / Q000096:biosynthesis*
D007288:Inosine; D000641:Ammonia; D014508:Urea; D005934:Glucagon; D000241:Adenosine; D004837:Epinephrine