Abstract

The effect of halothane exposure on synthesis of lung proteins was investigated. In rat lungs perfused in situ with Krebs-Henseleit bicarbonate buffer containing plasma levels of 19 amino acids, 690 µM [¹⁴C]phenylalanine, 5.6 mM glucose, and 4.5% bovine serum albumin, protein synthesis was linear for at least 4 hr. Halothane (1-4% equilibrated with O₂/N₂/CO₂, 4:15:1) rapidly inhibited protein synthesis in a dose-dependent manner, with about a 10% depression of the rate for each 1% increment in halothane. The inhibition was rapidly and completely reversed when halothane delivery was stopped; it was not associated with depletion of tissue ATP or with nonspecific changes in cellular permeability. A similar reversible and dose-dependent inhibition of protein synthesis was observed in primary cultures of mixed lung cells incubated in Dulbecco’s minimal essential medium containing 10% donor calf serum. These results suggested a significant but reversible inhibition of protein synthesis, exerted at the cellular level, in lungs exposed to halothane.