Biomedical subjects
Publications and source records attributed to P Langer.
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Biliary excretion of thyroxine (T4),3,5,3'-triiodothyronine (T3),3,3,5'-triiodothyronine (rT3) and diiodothyronines (3,3'-T2,3,5-T2 and 3',5'-T2) was estimated with the aid of radioimmunoassay in 3-4 subsequent 2-h samples of bile obtained from pentobarbital anesthetized rats through the tubing inserted in bile duct. The excretion of T3 was significantly decreased during 4-h infusion of 2400 ng/kg/min adrenaline in normal rats or during 6-h infusion of the latter dose in the animals preinjected with 2 micrograms T4. Moreover, the excretion of rT3 was significantly increased after the infusion of 1200 and 2400 ng/kg/min adrenaline. Such increase after 1200 and 2400 ng/kg/min adrenaline was prevented by a single dose of 10 mg/kg phentolamine (alpha 1-2-antagonist) and that after 2400 ng/kg/min adrenaline also by 2.5 mg/kg prazosin (alpha 1-antagonist) injected at the beginning of the infusion, but not by 6 mg/kg yohimbine (alpha 2-antagonist) injected every 60 min during 4-h infusion. In addition, increased rT3 excretion was found during the infusion of alpha 1-agonist methoxamine (1.5 mg/kg/4 h), while no such effect of the infusion of alpha 2-agonist azepexol (10 mg/kg/4 h) was observed. It may be suggested that the effect of adrenaline was mediated predominantly by alpha 1-adrenoceptors and that the observed changes in biliary excretion of T3 and rT3 were related to the inhibition of 5'-monodeiodination in the liver.
Thyrotrophin, thyroxine, triiodothyronine, and reverse triiodothyronine were measured in plasma and thyroxine and triiodothyronine in the thyroid gland of the rats flown for 18.5 days onboard Cosmos-1129. Postflight the plasma content of thyrotrophin and triiodothyronine increased and that of thyroxine decreased and the gland content of thyroxine and triiodothyronine diminished. It is postulated that in the flight animals the functional activity of the thyroid gland declined.