Changes in the hypothalamic interaction between norepinephrine and prostaglandin E2 during sexual maturation in female rats

The present experiments describe the study of the metabolism of 14C-arachidonic acid and the effect of exogenous norepinephrine (NE) on prostanoid production in the anterior preoptic area and medial basal hypothalamus (APOA-MBH) of prepubertal (16 days of age) and peripubertal female rats (30 days old). Four prostanoids were produced from 14C-arachidonic acid (6-keto-prostaglandin(PG)F1 alpha, PGF2 alpha, PGE2 and thromboxane (TX)B2) and were released to the incubating medium. The basal percent of conversion was not significantly different between them. In prepubertal rats the addition of NE (10(-5) M) to the medium did not modify on the synthesis of these eicosanoids. In peripubertal rats there are no significant differences in the basal production of 6-keto-PGF1 alpha, PGF2 alpha, PGE2 and TXB2 as compared to prepubertal rats. Moreover, the percentage of conversion of arachidonic acid into the different prostanoids was similar in prepubertal and peripubertal hypothalamus. Nevertheless, when NE (10(-5) M) was added to the incubation medium of peripubertal hypothalamus. Nevertheless, significant increase in the synthesis of PGE2 was observed (control: 1.75 +/- 0.1; NE 2.90 +/- 0.3; p < 0.01). This increase in the synthesis was not accompanied by changes in the synthesis of any of the other three prostanoids. Prazosin, a well-known alpha 1-receptor adrenoblocker at a dose of 10(-5) M did not modify the production of 6-keto-PGF1 alpha, PGF2 alpha, PGE2 and TXB2 but did induce a complete inhibition of the stimulation by NE of PGE2 synthesis (NE: 2.85 +/- 0.1; prazosin: 1.9 +/- 0.09; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)