Effects of Parathyroid Hormone on the Distribution and Transport of Calcium in Cultured Kidney Cells*

Abstract

The effects of parathyroid hormone (PTH) on the transport and distribution of Ca in isolated [monkey LLC-MK2] kidney cells were studied by kinetic analysis of 45Ca desaturation curves. PTH (15 ng/ml) increases the total cell Ca content, every exchangeable pool and all exchange rates. The greatest effect is observed in the slowest kinetic phase which reflects a mitochondrial pool. The effects of PTH occur even in the absence of Mg and of phosphate and the larger effect is again obtained in the mitochondrial pool. These results suggest that PTH stimulates Ca transport in kidney cells by affecting the intracellular distribution of Ca or by stimulating Ca influx.