Biotransformation of caffeine in human liver microsomes from foetuses, neonates, infants and adults.

1. Caffeine metabolism was studied in human liver microsomes from foetuses (n = 10), neonates (n = 10), infants (n = 9) and adults (n = 5). Caffeine and its metabolites, 1-3-7-trimethyluric acid, paraxanthine, theophylline and theobromine, were assayed by h.

Lack of alteration in cardiac beta-adrenoceptor site concentration in rats treated with an adenylate cyclase-stimulating dose of endotoxin.

In previous experiments on male rats we showed that 2 mg kg-1, intravenously, lipopolysaccharide from Escherichia coli, a sublethal nonhypotensive dose, induced circulating cardiodepressant activity, maximal alterations in steroid hormonal response, and myocardial adenylate cyclase hyperactivity 4 h later. The purpose of the present study was to investigate a possible relation between this adenylate cyclase hyperactivity and alterations in total ventricular beta-adrenoceptors. To this end, ventricular beta-adrenoceptor concentration and affinity were measured under the same conditions.

Effect of pregnandiol on caffeine metabolism in female rats.

Three groups of six 5-week-old Sprague Dawley female rats received i.p. injections of pregnandiol, 1.

Caffeine metabolism in liver slices during postnatal development in rats.

The metabolism of caffeine was investigated in liver slices from newborn, preweanling, postweanling, and adult rats. All metabolites were identified and quantified by HPLC without using radioactive compound. Caffeine metabolism underwent dramatic changes during maturation in rats.

Could saliva stand for plasma in theophylline monitoring in asthmatic children? Still a controversial problem.

Theophylline determination in saliva was proposed several years ago as a convenient and non-invasive alternative to monitoring plasma in children and adults. Published data demonstrated that theophylline saliva concentration linearly correlates plasma concentration. However, the variability found in interindividual serum/saliva ratios and the wide scattering among the data points precluded the clinical use of saliva for theophylline monitoring.