Tissue uptake of 3H-methylprednisolone in acute myocardial ischemia.

The tissue uptake of 3H-methylprednisolone (3H-MP) was studied in anesthetized cats during acute myocardial ischemia 1 and 2 hours after injection of 3H-MP. There was a rapid uptake of 3H-MP by many tissues. Liver, kidney, and pancreas exhibited tissue/perfusion ratios of 3 to 7, heart, lungs, and intestine about 2, spleen, adrenal, and aorta 1 to 2, and skeletal muscle and omentum less than 1. Very similar tissue uptakes occurred in cats subjected to myocardial ischemia and sham myocardial ischemia at 1 and 2 hours. Plasma clearances of 3H-MP was not significantly altered either 1 or 2 hours after the onset of myocardial ischemia. Although ischemic myocardial tissue took up less than nonischemic myocardial tissue, this region accumulated significant amounts of 3H-MP. Myocardial tissue metabolized only about 15 to 20 per cent of the 3H-MP taken up after 2 hours. These data indicate that in acute myocardial ischemia, myocardial tissue takes up large amounts of exogenously administered glucocorticoid, most of which remains in the native form during the early phase of acute myocardial infarction.