The lung as a target organ for thyroxine

: The isolated perfused in situ rat lung preparation was used to investigate the chronic effect of thyroxine on the intermediary metabolism in the mammalian lung. Treatment with thyroxine caused stimulation of the rate of glucose utilization (91 +/- 11 mumol/g dry weight/hr versus 54 +/- 5 mumol/g dry weight/hr). The increase in the rate of glucose uptake was not accompanied by a similar increase in lactate output. Alanine and pyruvate release were also similar in both groups. The implication is that oxidative metabolism of glucose was increased. This study provides the first unequivocal evidence that the mammalian lung is a target organ for thyroxine.