The effect of oestradiol-17 beta and progesterone on uptake1, uptake2 and on release of noradrenaline in the uterine artery of ovariectomized pigs.

Influence of oestradiol-17 beta and progesterone on neuronal uptake (U1) and extraneuronal uptake (U2), and on the spontaneous neuronal and tissue release of noradrenaline was investigated in isolated uterine artery obtained from an ovariectomized pigs. It was found that oestradiol decreased U1 by 38.7% (p < 0.05), U2 by 78.2% (p < 0.01) and neuronal release by 55.4-63.0% (p < 0.05). Progesterone decreased U2 by 80.5% (p < 0.01) and neuronal release by 71.7-76.4% (p < 0.01). Simultaneous administration of oestradiol and progesterone led to the inhibition of U2 by 93.9% (p < 0.01) and neuronal release by 69.6-73.8 (p < 0.01) and to the rise of tissue release by 72.2-87.5% (p < 0.05-p < 0.01). Oestradiol inhibited noradrenaline uptake and decreased it reserves in uterine artery of pigs. This consequently decreased vasospastic adrenergic influence in the oestrous phase of the cycle. Effect of progesterone on the noradrenaline uptake was similar to that caused by oestradiol. Quantitative differences in the action of these hormones on noradrenaline uptake were not significant and did not explain their different influence on the vasotonus of the reproductive tract.