Effect of gender on development and diurnal rhythm of prostaglandin receptors in rat aorta.

1 The prostaglandin endoperoxide H2 analogue, U-46619 (15-hydroxy-11, 9-epoxymethanoprosta-5Z, 13E-enoic acid), was used to determine the effect of gender on the isotonic contractile response of the superfused rat aorta preparation over a 24 h period and at 10 and 16 weeks of age. 2 The maximal responses of the male aortae were 20 +/- 3% and 36 +/- 4% (P less than 0.001) greater than the female at 10 and 16 weeks, respectively. Similarly, sensitivity of the male aorta to the PGH2 analogue increased with age. 3 The male but not the female exhibited a diurnal rhythm in which both the maximum contractile response and sensitivity were significantly decreased at night. 4 We conclude that these gender differences may be related to the secretion of androgen, since reported peak serum testosterone over a 44 h period and testosterone changes with maturation are coincident with the maximum response of male aortae to the PGH2 analogue.