RESUMO
The effect of adrenalectomy on the formation of cyclooxygenase and lipoxygenase products from [1-14C]-arachidonic acid in rat kidneys after incubation with the Calcium-ionophore A23187 has been determined. The metabolites were isolated by HPLC. The main components formed are PGD2, PGE2, PGF2 alpha, LTB4, 5,12 di-HETE and 5-, 12- and 15-HETE. After adrenalectomy, an increase occurs in the formation of PG and LT, which is highest in that of PGD2 and 12-HETE. These effects are most probably related to a diminished formation or inactivation of lipocortin in adrenalectomized animals, a glucocorticosteroid induced peptide with phospholipase A2 inhibitory activity.
Assuntos
Glândulas Suprarrenais/fisiologia , Araquidonato Lipoxigenases/metabolismo , Rim/metabolismo , Prostaglandina-Endoperóxido Sintases/metabolismo , Adrenalectomia , Animais , Ácido Araquidônico , Ácidos Araquidônicos/metabolismo , Masculino , Ratos , Ratos EndogâmicosRESUMO
The effect of adrenalectomy on the formation of cyclo-oxygenase and lipoxygenase products by activated peritoneal rat macrophages was determined and compared with that of the spleen. After isolation, the cells and tissues were incubated with [1-14C] arachidonic acid and the Ca-ionophore A23187 and the metabolites isolated by HPLC chromatography. The main components formed in the macrophages of the controls are 6-keto-PGF1 alpha, TxB2 and 12-HETE. One peak represents 5, 12 di HETE. Smaller amounts of PGF2 alpha, PGE2, PGD2, LTB4 and 15-HETE are also present. After adrenalectomy, a considerable increase occurs in the amounts of LTB4, 15-HETE and 12-HETE. The increase in the PG is smaller. The compounds formed from endogenous arachidonic acid are also determined. In the cells of the controls, the formation of LTB4 is considerably increased after adrenalectomy. In the spleen, PGD2 and 12-HETE are decreased after adrenalectomy. The effect of the macrophages is most probably related to a diminished amount or inactivation of lipocortin, a glucocorticosteroid induced peptide with PlA2 inhibitory activity in adrenalectomized animals. In the decrease in formation in the spleen, the absence of the permissive effect of glucocorticosteroids on the hormone-induced lipolysis may play a role.
