Nafazatrom, an arachidonate metabolism inhibitor, decreases prolactin and GH release

Nafazatrom, an inhibitor of arachidonate metabolism by the lipoxygenase enzymes, decreases basal prolactin and growth hormone release in a concentration-dependent manner without significantly affecting the synthesis of either hormone. It is required that nafazatrom be incubated with pituitary cells for approximately 2 h for this effect to become evident; the blockade increases in magnitude for up to 4 h. Nafazatrom blocks the increase in prolactin release caused by the releasing factors TRH and angiotensin II and the increase in prolactin and growth hormone release due to the calcium channel activator maitotoxin. These data suggest that the lipoxygenase products of arachidonate metabolism may be important mediators in basal and secretagogue-induced release of prolactin and growth hormone.