プロラクチンの家兎の心脈管系に対する作用とその機序の検討
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概要
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It has been suggested that prolaction (PRL) may be responsible for blood pressure regulation in mammals. However, the physiological and pathophysiological roles of PRL are still controversial. This study was designed to determine the direct effect of ovine PRL on the cardiovascular system using Langendorff's isolated perfused hearts and hinderlimb perfusion preparations from 64 rabbits. 1) The hearts were perfused with the perfusate whichl contained ovine PRL of 50 ng/ml, 100 ng/ml and 500 ng/ml. There were almost no changes in submaximum active tension, heart rate and coronary flow by PRL perfusion. Norepinephrine was cummulatively infused to the hearts at a rate of 1×10^<-6> g/min to 1×10^<-3> g/min, and no shift of dose-response curve of active tension was observed in each PRL concentration. 2) In the hinderlimb preparations, there was no significant difference of basal flow among control group and groups with 50 ng/ml, 100ng/ml and 500 ng/ml of PRL in the perfusate. 3) Dose-response curve of hinderlimb flow to norepinephrine which was cummulatively administered to the hinderlimb preparations by the same way as mentioned above was observed and it was most significantly shifted to the left in the group of 50 ng/ml and followed by the group of 100 ng/ml and 500 ng/ml. These results suggest that PRL itself may have no significant direct effects on the cardiovascular system, but may enhance the responsiveness of the peripheral vessels to norepinephrine. From these findings, it is indicated that PRL may possibly participate in the regulation of blood pressure.
- 神戸大学の論文