Salsolinol induces a decrease in cyclic AMP at the median eminence and an increase at the adenohypophysis in lactating rats

Investigating the cellular events in the pituitary gland, the intracellular cyclic AMP (cAMP) of the median eminence (ME), neuro-intermediate lobe (NIL) and the anterior lobe (AL) have been measured following 15-min of intravenous injection of salsolinol (SAL). Parallel to the elevation of plasma prolactin (PRL), SAL induced a significant decrease of cAMP concentration in the ME. In contrast, SAL injection resulted in a significant increase of cAMP at the level of the AL. Changes in cAMP of the NIL as well as in the plasma level of vasopressin (VP) could not be detected. The observed changes in the level of cAMP following the acute treatment of SAL in the ME and the AL seems to be related to interacting neuroendocrine signals delivered from the ME to the AL through the long portal vessels to release PRL.