Changes in transport functions of isolated rabbit choroid plexus under the influence of oestrogen and progesterone

Isolated choroid plexuses from rabbits were used to determine uptake and accumulation of 10^-5 M radiolabelled choline (expressed as tissue/medium ratio) and the activities of various types of ATPases (based on ouabain inhibition and bicarbonate stimulation) following pre-treatment of the animals with 0.5 mg kg^-1 17-β-oestradiol, alone or in combination with 2 mg kg^-1 progesterone. The combined treatment reduced the choline uptake by 35% and also lowered the activity of Na⁺, K⁺-ATPase by 31%, without influencing tissue wet weight. The reduction in HCO₃-ATPase was smaller and not statistically significant. There was a tendency also for oestrogen alone to lower these activities, but only by less than 20%. The Ca²⁺, Mg²⁺-ATPase activity was not significantly affected by any of the hormones.