title: Contribution of lungs to desipramine-induced changes in whole body catecholamine kinetics in newborn lambs.
abstract: To characterize pulmonary and total body norepinephrine and epinephrine kinetics in the immediate newborn period, the effects of desipramine were studied in six fetal lambs chronically instrumented at 133-134 days gestation (term 147 days) and delivered 1 wk later by cesarean section under spinal anesthesia. Norepinephrine and epinephrine kinetics were determined with isotope dilution methodology 4 h after birth and repeated 30 min after desipramine (2 mg/kg iv). At baseline, the lungs accounted for 35 +/- 10 and 47 +/- 13% of whole body norepinephrine clearance (93 +/- 8 ml. min-1. kg-1) and spillover (188 +/- 29 ng. min-1. kg-1) and 15 +/- 2 and 19 +/- 7% of whole body epinephrine clearance (82 +/- 4 ml. min -1. kg -1) and release (22.7 +/- 2.7 ng. min-1. kg-1), respectively. Desipramine decreased pulmonary norepinephrine and epinephrine clearance and spillover to near-zero levels, whereas whole body norepinephrine clearance fell by 51 +/- 3% (P < 0.001), norepinephrine spillover by 54 +/- 6% (P < 0.005), epinephrine clearance by 30 +/- 6% (P < 0.01), and epinephrine spillover by 34 +/- 11% (P < 0.05). These results indicate that, in the immediate newborn period, pulmonary removal and release of norepinephrine and epinephrine is mediated by a desipramine-sensitive process that accounts for a major portion of associated reductions in whole body norepinephrine and epinephrine clearance and release.
authors.affiliation: Institute of Reproduction and Development, Victoria 3181, Australia.
authors.forename: J J
authors.initials: JJ
authors.lastname: Smolich
authors.forename: H S
authors.initials: HS
authors.lastname: Cox
authors.forename: M D
authors.initials: MD
authors.lastname: Esler
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism / Q000502:physiology*; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology*; D004837:Epinephrine / Q000097:blood / Q000378:metabolism*; D005740:Gases / Q000097:blood; D006439:Hemodynamics / Q000187:drug effects; D007700:Kinetics; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D009638:Norepinephrine / Q000097:blood / Q000378:metabolism*; D011652:Pulmonary Circulation / Q000187:drug effects; D012756:Sheep
chemical_list: D000929:Antidepressive Agents, Tricyclic; D005740:Gases; D003891:Desipramine; D009638:Norepinephrine; D004837:Epinephrine