Effect of lanthanum on the turnover of calcium in rat uterus.

Previous investigations suggest that lanthanum might enter uterine smooth muscle cells and work as intracellular calcium displacing agent. The present investigation had been carried out in order to confirm if lanthanum develops an intracellular effect. Experiments show that lanthanum brings about a marked increase of the intracellular calcium; the comparison of the uptake and of the wash-out curve of 45Ca shows that lanthanum induces a lowering of the rapid phase of 45Ca release from rat uterus, while the uptake of the labelled ion is not modified or is even enhanced. The present data demonstrate that the action of lanthanum in rat uterus is limited to the cell membrane, whose calcium extruding properties are inhibited.