Weanling rats were fed for 4 weeks semipurified diets containing 0, 100 or 300 mg 13- cis retinoic acid per kg diet. The activities of ( Na + + K +)-ATPase, Mg 2+-ATPase and γ-glutamyltranspeptide were measured in submandibular salivary gland (SMSG) homogenates. The activity of ( Na + + K +)-ATPase in the SMSG was reduced in rats fed 13- cis retinoic acid. There was no effect on the activities of the other two enzymes. Fatty acid composition of total lipids in SMSG suggest that decrease in ( Na + + K +)-ATPase activity may be associated with changes in fatty acid composition of total lipids.