Possible involvement of lipoxygenase pathway of arachidonic acid in rat pituitary hormone release in vitro.

The roles of arachidonic acid (AA) and its lipoxygenase products in control of secretion of anterior pituitary hormones were studied in vitro using cultured cells. AA (10(-4)M) and 5-hydroxy-eicosatetraenoic acid (5HETE) (5 x 10(-6)M) significantly (p less than 0.05) stimulated the releases of LH, TSH, GH, PRL, ACTH and beta-endorphin (beta-E). Added leukotriene B4 (LTB4) (5 x 10(-6)M) also caused significant increases in the secretions of LH, GH, ACTH and beta-E. The other lipoxygenase metabolites tested, 12HETE, 15HETE, LTA4, LTC4 and LTD4, had no effect on the releases of anterior pituitary hormones. These results suggest that AA and 5-lipoxygenase metabolites may be involved in the control of the releases of anterior pituitary hormones.