title: Restitution of myocardial adenine nucleotides: acceleration by administration of ribose.
abstract: In the present study, the influence of ribose on the biosynthesis of myocardial adenine nucleotides was examined in rats in vivo utilizing two experimental models which are characterized by a reduction in the adenine nucleotide content; recovery from oxygen deficiency and application of isoproterenol. 1. The biosynthesis (= de novo synthesis) of cardiac adenine nucleotides was enhanced by 90% during the first 60 min of recovery from five intermittent periods of asphyxia of 4.5 min duration (Table I). 2. Isoproterenol induced a stimulation of myocardial adenine nucleotide synthesis in a dose-dependent manner amounting to 640% three hours after s.c. administration of 25 mg/kg (Fig. 1). 3. Ribose which bypasses the hexose monophosphate shunt in the myocardium and which leads to an elevation of the available pool of 5-phosphoribosyl-1-pyrophosphate (PRPP), stimulated the biosynthesis of adenine nucleotides in the heart, but not in liver and kidney, of rats one hour after i.v. application of a single dose of 100 mg/kg from 6 nmoles/g/h to 27 nmoles/g/h (Fig. 2). 4. When ribose was constantly infused during the first 60 min of recovery from asphyxia, the enhancement of cardiac adenine nucleotide biosynthesis was further stimulated from 12.6 nmoles/g/h to 20.5 nmoles/g/h (with 500 mg ribose/kg/h) and to 43.4 nmoles/g/h (with 1 000 mg ribose/kg/h) (Fig. 3). 5. Continuous I.V. infusion of ribose (200 mg/kg/h) for 24 hours in isoproterenol-treated rats during a 13-fold increase in myocardial adenine nucleotide biosynthesis compared with the control (Fig. 4). In this condition, the isoproterenol-induced decline in the adenine nucleotide level did not occur (Table II).
mesh_terms: D000227:Adenine Nucleotides / Q000096:biosynthesis*; D000818:Animals; D001237:Asphyxia / Q000378:metabolism*; D004357:Drug Synergism; D005260:Female; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009928:Organ Specificity; D010754:Phosphoribosyl Pyrophosphate / Q000378:metabolism; D051381:Rats; D012266:Ribose / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000227:Adenine Nucleotides; D012266:Ribose; D010754:Phosphoribosyl Pyrophosphate; D007545:Isoproterenol