Dual role of glucocorticoids in suckling-induced prolactin secretion

The exact contribution of corticosteroids to the control of prolactin secre tion in lactating rats is poorly understood. Therefore, the present studies were focused on the effect of adrenalectomy and dexamethasone treatment on the suckling-induced prolactin release. Animals were adrenalectomized on t he 3rd day of lactation and tested on the 7th day of lactation. In adrenale ctomized animals, the suckling stimulus failed to induce the characteristic increase in plasma prolactin levels. Dexamethasone pretreatment (400 mug/k g b.w. s.c. 24, 48, 72 h before testing) of adrenalectomized rats restored this prolactin response. The same treatment with dexamethasone given to con trol animals attenuated the suckling stimulus induced prolactin response. T he present findings indicate that corticosteroids are essential for a basic prolactin response of lactating rats.