Preincubation of cells in the presence of 4% ethanol accompanied by an increase of non-saturated cis-vaccenic acid content was shown to promote synthesis of alkaline phosphatase. Preincubation of cells in 0.1% hexanol reducing the level of this acid, on the contrary, leads to partial repression of the enzyme synthesis; the lag-phase of repression in the cells with a raised content of non-saturated cis-vaccenic acid and, consequently, with a greater fluidity of lipids was also shown to be reduced. Conversely, the reduction of lipid membrane fluidity on ethanol addition simultaneously with the repressing metabolite ortho-phosphate extends the lag-phase of repression and removes it partially during cell cultivation in the presence of ortho-phosphate. The impact of lipid composition variations on the synthesis and repression of alkaline phosphatase is discussed.