Lungs metabolic

The pulmonary absorption and metabolism of an opioid tetrapeptide was investigated in the IPL and in rats in vivo by Tronde and co-workers [68, 140], The lung metabolism, compared after airway and vascular delivery, was consistently showed to be higher after airway delivery indicating some first-pass... 

Longmore WJ (1982) The isolated perfused lung as a model for studies of lung metabolism. In Farrel PM (ed.) Lung Development Biological and Clinical Perspectives. Academic Press Inc, New York, pp 101-110. 

Lung metabolism studies would greatly benefit from the availability of reliable in vitro experimental models that are able to reproduce biochemical and toxicological processes that occur in the human lung. Because of differences in the expression profiles of biotransformation enzymes between animal species, conclusions drawn from experimental animals may not be representative of what occurs in the human lung. 

Nicotine is well absorbed from the mucous membranes in the oral cavity, gastrointestinal tract, and respiratory system. If tobacco smoke is held in the mouth for 2 seconds, 66 to 77% of the nicotine in the smoke will be absorbed across the oral mucosa. If tobacco smoke is inhaled, approximately 90 to 98% of the nicotine will be absorbed. Nicotine is distributed throughout the body, readily crossing the blood-brain and placental barriers. The liver, kidney, and lung metabolize approximately 80 to 90% of the alkaloid. The kidney rapidly eliminates nicotine and its metabolites. 

Pharmacokinetics Onset of action is rapid with duration of 4-8 hr. Rapidly absorbed following aerosol administration. Primarily distributed to lungs. Metabolized in liver. Excreted in urine and feces. Half-life 3 hr... 

Evelo, C.T.A., Oostendorp, J.G.M., Ten Berge, W.F. Borm, P.J.A. (1993) Physiologically based toxicokinetic modeling of 1,3-butadiene lung metabolism in mice becomes more important at low doses. Environ. Health Perspect., 101, 496-502... 

Type I cells are alveolar lining cells that are involved with the transfer of substances from the alveolus through the wall to the blood. Type II cells are alveolar cells with two functions oxidative enzymes for lung metabolism, and the production and secretion of the surfactant coating the alveolar surface. 

No studies regarding absorption in humans after inhalation exposure to di- -butyl phthalate were located. The relatively low concentration of di- -butyl phthalate found in the lungs of rats exposed to 50 mg/m of di- -butyl phthalate for up to 6 months was suggested to indicate rapid absorption (Kawano 1980b). However, no metabolites were measured in this study, and so the lack of accumulation could be due to lung metabolism rather than absorption. 

Ward, J.K. Dow, J. Dallow, N. Eynott, P. Milleri, S. Ventresca, G.P. Enantiomeric disposition of inhaled, intravenous and oral racemic-salbutamol in man-no evidence of enantioselective lung metabolism. Br. J. Clin. Pharmacol. 2000, 49, 15-22. 

Fletcher, J.R. and Ramwell, P.W. (1977). Altered lung metabolism of prostaglandins during hemorrhagic and endotoxin shock. Surg. Forum, 28, 184-186... 

These substances are metabolized in the liver and to a lesser extent in the kidneys and lungs. Metabolism is higher with halothane (20-46%), followed by enflurane (2.4-8.5%), sevoflurane (2.5-3.3%), isoflurane (0.2%) and desflurane (0.02%). So their determinations are intended to find drugs, not metabolites. The following concentrations in blood have been found in deaths related with these substances (Table 7). 

Maritz, G. S., 1993, The influence of maternal nicotine exposure on neonatal lung metabolism Protective effect of ascorbic acid. Cell Biol. Internat. 17 579-585. 

Rhoades, R. A., and Ryder, D. A., 1981, Fetal lung metabolism response to maternal fasting, Biochim. Biophys. Acta 633 621-629. 

Date H, Matsumura A, Manchester JK, Obo H, Lima O, Cooper JM, Sundaresan S, Lowry OH, Cooper JD. Evaluation of lung metabolism during successful twenty-four hour canine lung preservation. J Thorac Cardiovasc Surg 1993 105 480 91. 

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