The metabolic action of gestagens on the cerebral cortex of the guinea pig.

The injection of chlormadinone acetate (CA) or norgestrel (N) potentiated the effects of estradiol (E₂) on RNA synthesis in the guinea pig cerebral cortex, but not in the uterus. Only CA inhibited the stimulation of protein synthesis by E₂ in the cerebral cortex. In contrast, the E₂-induced increment of protein synthesis in the uterus was not affected by the administration of either gestagen.When injected alone neither gestagen showed any metabolic action on the brain, indicating that their effects on RNA and protein synthesis in the cerebral cortex requires the presence of E₂.