Summary Luteinizing hormone releasing hormone stimulates the concomitant release of luteinizing hormone and 45Ca 2+ from prelabeled anterior pituitary cells. Indomethacin (10 μM) and nordihydroguaiaretic acid (10 μM) had no effect on the luteinizing hormone releasing hormone-stimulated release of either luteinizing hormone or 45Ca 2+. Eicosatetraynoic acid (10 μM) blocked both luteinizing hormone releasing hormone-stimulated luteinizing hormone secretion and luteinizing hormone releasing hormone-stimulated 45Ca 2+ efflux. 5,6-Epoxyeicosatrienoic acid stimulated both luteinizing hormone secretion and 45Ca 2+ efflux from anterior pituitary cells. Additionally, 5,6-epoxyeicosatrienoic acid closely mimics the ability of luteinizing hormone releasing hormone to increase intracellular free calcium. These results are consistent with the hypothesis that 5,6-EET alters calcium homeostasis in a manner similar to that observed during luteinizing hormone releasing hormone stimulation of luteinizing hormone release.