Actions of quinacrine on RNA and casein syntheses in mouse mammary gland explants.

Quinacrine at concentrations of 0.025 mM and greater significantly reduced or abolished the prolactin stimulation of RNA synthesis in mouse mammary gland explants. At concentrations of 0.01 mM or greater, the stimulatory action of prolactin on [3H]-leucine incorporation into a casein-rich protein fraction was also reduced or abolished. The possible relationship of these actions of quinacrine to its inhibition of phospholipase A2 and/or prostaglandin biosynthesis is discussed.