5,6-Epoxyeicosatrienoic acid stimulates growth hormone release in rat anterior pituitary cells

The effect of arachidonic acid and some of its metabolites have been examined in rat anterior pituitary cells for their ability to release growth hormone. The cytochrome P-450 metabolite, 5,6-epoxyeicosatrienoic acid is a much more effective growth-hormone releasing agent than 15-hydroxyeicosatetraenoic acid, 15-hydroxyeicosatetraenoic acid methyl ester, 5-hydroxyeicosatetraenoic acid or arachidonic acid. The release of growth hormone is rapid, dose-dependent and reaches an apparent saturation after eight minutes. These studies described herein provide evidence that lipoxygenase and cyclooxygenase products of arachidonic acid are less potent while cytochrome P-450 products are more potent in the release of growth hormone from anterior pituitary cells.