Insulin and Cortisol Improve Heat Tolerance in Isolated Perfused Rat Liver

摘要

Isolated rat livers were perfused at 37, 41, 42, and 43 C with and without insulin and cortisol. Two additional groups were perfused at 42 C with either hormone alone. The perfusate contained red blood cells, amino acids, and albumin in Krebs-Ringer bicarbonate. Bile flow was significantly increased by hormones at 37 C. Bile flow was increased by hormones at all other temperatures. At 41 C, K(+) leakage was the only parameter that indicated injury. Insulin and cortisol significantly reduced K(+) leakage at this temperature compared to those without hormones. At 42 C, insulin and cortisol reduced K(+) leakage, increased bile flow, reduced transaminase release, and improved ultrastructural integrity. The enhanced bile flow was due primarily to insulin. A reduction in K(+) leakage required both insulin and cortisol. Transaminase leakage responded to either hormone alone or in combination, however, only the cortisol-treated group showed a statistically significant reduction in transaminase leakage. At 43 C, indication of irreversible injury were evident and hormones had no beneficial effects. Loss of membrane homeostasis appeared to be initial event.