title: The effects of age and dietary protein restriction on the pharmacokinetics of theophylline in the rat.
abstract: The influence of dietary protein levels on theophylline kinetics was examined in male Fischer 344 virgin rats of 2, 14 and 20 months of age fed for four weeks on a 23% (control) or 5% (low) protein diet ad libitum. Protein deficiency led to a significant decrease in body weight gain for the 2 month old rats (10.9% versus 26.5%). In addition, decreases in total body weight of 7.5% and 15.3% were seen for the 14 and 20 month old rats, respectively, on a low protein diet. Total proteins and albumin levels in plasma were not significantly affected by age or dietary protein levels. After intravenous administration of 10 mg/kg aminophylline, the average mean residence time (MRT) was significantly longer in 20 month old rats as compared to the younger rats, while 14 month old rats had a greater elimination rate constant than the 2 and 20 month old rats. There were significant reductions in the mean steady-state apparent volume of distribution (Vss) in the 2 and 14 month old rats on a low protein diet of 31% and 18%, respectively, while there was no difference between the diets in 20 month old rats. In addition, the Vss decreased from 0.71 L/kg to 0.57 L/kg in the 2 and 20 month old rats, respectively, on a normal protein diet. Dietary protein deficiency led to a significant reduction of total body clearance from approximately 73 to 45 ml/hr/kg in the 2 and 14 month old rats.2+p
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Illinois, Chicago.
authors.forename: D
authors.initials: D
authors.lastname: Jung
authors.forename: M
authors.initials: M
authors.lastname: Nanavaty
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D007732:Kwashiorkor / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D011488:Protein Deficiency / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013806:Theophylline / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D013806:Theophylline