title: Effect of age on antipyrine metabolism in patients with gastric cancer.
abstract: The metabolism of antipyrine was studied in 19 male patients with gastric cancer. Three groups of subjects were chosen for the study: 4 patients 46--51 years of age (group 1), 8 patients 52--61 years old (group 2), and 7 patients 62--75 years old (group 3) matched for sex, smoking, alcohol intake, renal function, and liver function. The mean half-life (t 1/2) of antipyrine in group 3 (15.6 +/- 4.8 hr) was significantly longer than that in group 1 (8.1 +/- 0.9 hr, P < 0.01). Similarly, the mean metabolic clearance rate (MCR) in group 3 (246 +/- 78 ml/hr/kg) was significantly lower than that in group 1 (498 +/- 175 ml/hr/kg, P < 0.02). Significant correlations were observed between age and the t 1/2 of antipyrine (r = 0.592, P < 0.01) and between age and MCR (r = -0.499, P < 0.05). The plasma of 8 patients was tested for testosterone levels. Significant correlations were observed between plasma testosterone levels and both the t 1/2 of antipyrine (4 = -0.783, P < 0.05) and MCR (r = 0.912, P < 0.001). These observations indicate that drug-metabolizing ability might decline with age in cancer patients.
mesh_terms: D000367:Age Factors; D000368:Aged; D000983:Antipyrine / Q000097:blood / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000097:blood*; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone; D000983:Antipyrine