| Research Abstract |
Arachidonate can be released from plasma membrane phospholipid by various agonist such as hormones and metabolized to various eicosanoids via cyclooxygenase (CO), lipoxygenase (LO) and P-450 dependent monooxygenase pathways (MO). Recently it has been reported by several investigators that those eicosanoids may play an important role in regulation of hormone secretion in various endocrine organs.
1) An intermediate metabolite of AA-5LO e.g. 5HPETE may play an important role in the conversion of cholesterol into pregnenolone by side-chain cleavage enzymes in rat adrenal fasciculata cells. We also found the existence of 5 and 15LO and P-450 MO in bovine adrenal fasciculata cells. In bovine adrenal fasciculata cells, metabolites of P-451 MO, such as 5,6-, 8,9-, 11,12- and 14,15-EETs were found to be able to stimulate cortisol secretion.
2) In rat hepatocytes, existence of P-450 dependent monooxygenase were postulated the metabolites of P-450 MO (5,6-, 8,9-, 11,12-, 14,15-EETs) were found to stimulate phosphorylase activity, resulting in the enhancement of conversion of glycogen into glucose EETs were found to enhance, intracellular accumulation of Ca^<++>, suggesting that EETs may act via stimulation of Ca^<++> messenger system.
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