A reduction in tubulin mRNA levels up to 35-40 min following pressure (10,000 psi for 5 min) was shown by cDNA hybridization in log growth phase and deciliated Tetrahymena. The level of tubulin mRNA increased to a maximum 1 hour after pressure release. Poly(A+) mRNA derived from pressure-treated and atmospheric control cells following deciliation was translated in vitro. The profile for tubulin synthesized in vitro closely resembled the tubulin mRNA profiles. In vivo tubulin synthesis measured by 35S methionine incorporation was suppressed 60%, 40 min following pressure release. The data supports the hypothesis that both transcription and post transcriptional events are sensitive to hydrostatic pressure.