title: Disposition of 5-hydroxytryptamine in lungs of developing rats.
abstract: The pulmonary vasculature has been implicated in the clearance of several vasoactive peptides, prostaglandins, and biogenic amines from the circulation. In view of the age-related differences in the metabolism of angiotensin by intact lungs, it was of interest to examine the maturation of 5-hydroxytryptamine (5-HT) disposition by isolated perfused lungs. Lungs from newborn and adult rats were perfused with Krebs bicarbonate buffer containing 0.1 microM 5-[14C]HT and samples of the effluent medium collected and analyzed for 5-HT and metabolite. Adult lungs removed and a greater fraction of perfused 5-HT than did lungs from 7-day-old rats. No age-related difference in monoamine oxidase (MAO) activity was observed; however, lung slices from adult rats incubated with 5-[14C]HT accumulated radiolabel at a greater rate than did slices from lungs of 7-day-old rats. The age-related difference in 5-HT clearance by intact lungs may be attributable to a relative deficiency in the facilitated transport process for 5-HT in newborns and may reflect a general functional maturation of processes associated with pulmonary endothelial cell membranes.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport; D008168:Lung / Q000378:metabolism*; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000378:metabolism*
chemical_list: D012701:Serotonin; D008995:Monoamine Oxidase