Effect of thyroxine on permeability of the neonatal rat lung to drugs.
The effect of thyroxine (1-2 microgram/g i.p. on days 1-4 after birth) on development of adult-type permeability characteristics in the lung was investigated in rats 6-18 days of age. In both treated and control rats, the lipid-soluble drug procaine amide was absorbed at similar rates in all age groups. In contrast, in thyroxine-treated animals, pulmonary absorption rates for the lipid-insoluble compounds mannitol and p-aminohippuric acid declined to adult levels at age 6-12 days, 6 days earlier than in controls. Thyroxine treatment thus accelerates development of adult permeability characteristics in the pulmonary epithelium.
D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D007274:Injections, Intraperitoneal; D008168:Lung / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000378:metabolism*; D011342:Procainamide / Q000378:metabolism*; D051381:Rats; D013974:Thyroxine / Q000008:administration & dosage / Q000494:pharmacology*; D010130:p-Aminohippuric Acid / Q000378:metabolism*
D000618:Aminohippuric Acids; D008353:Mannitol; D011342:Procainamide; D013974:Thyroxine; D010130:p-Aminohippuric Acid