Arachidonic acid-induced hormone release in somatotropes: involvement of calcium.

Arachidonic acid (AA) has been implicated in signaling actions in several cell types including endocrine cells. In the present study, we investigated the effect of exogenous AA on GH release from dispersed pituitary cells and tried to elucidate the mechanism involved in this process. We show that AA stimulates GH release in a dose- and extracellular calcium-dependent manner.

Arachidonic acid increases cytosolic calcium and stimulates hormone release in rat lactotrophs.

Arachidonic acid (AA) released from membrane phospholipids after activation of surface receptors causes cellular signaling actions in neurons and endocrine cells, including stimulation of prolactin (PRL) release from dissociated rat pituitary cells and clonal cells of the GH3 pituitary tumor line. In the present study, we investigated the effect of exogenous AA on PRL release from dispersed pituitary cells and tried to elucidate the mechanism involved in this process. The effects of AA on cytosolic Ca2+ concentration ([Ca2+]i) were studied using dual-emission microspectrofluorometry in identification lactotrophs and on PRL release in dispersed pituitary cell populations.

Prolactin and growth hormone release and calcium influx are stimulated by galanin within a 'window' range of concentrations in pituitary GH3 B6 cells.

Galanin is widely distributed throughout the rat neural and endocrine system with the highest concentration in the anterior pituitary. The effects of galanin were investigated in rat tumor pituitary cells (GH3/B6). A single stimulation with galanin caused prolactin (PRL) and growth hormone (GH) release within a narrow range of concentrations (10(-11)-10(-9) M).

[Long-term induced effects by only one treatment with ketoconazole on rat tumoral pituitary cells (GH3/B6 strains)].

Ketoconazole, an imidazole is a powerful antimycotic that has recently been used in the treatment of endocrinological and lipid metabolism disorders as well as in anti-cancer chemotherapy. When rat mammosomatotropic cells are treated for 30 hrs., this drug produces different effects depending on whether cells are normal or tumoral (GH3/B6).

Galanin evokes a cytosolic calcium bursting mode and hormone release in GH3/B6 pituitary cells.

The effects of galanin on secretion and cytosolic free Ca2+ concentration ([Ca2+]i) have been studied in GH3/B6 pituitary cells. Prolactin (PRL) and growth hormone (GH) release was measured in column perifusion experiments; [Ca2+]i was monitored in single cells by dual emission microspectrofluorimetry using indo-1 as intracellular Ca2+ probe. Galanin (0.