The ultrastructure of renomedullary interstitial cells in hypercalcemia induced by calcium gluconate.

Under hypercalcemia induced by calcium gluconate the degranulation of renomedullary interstitial cells accompanied with the increase in volume of the rough and smooth surfaced endoplasmic reticulum and enlargement of the Golgi apparatus were observed. The ultrastructural changes can be regarded as an expression of the increase of a synthetic and secretory activity of these cells. Because the changes of renomedullary cells observed in hypercalcemia induced by calcium gluconate are not really different from that observed in hypercalcemia induced by vitamin D3 (Roszkiewicz et al. 1979) it can suppose that these changes may be connected solely with a calcium serum elevation and that the renomedullary interstitial cells rather do not play any important role in vitamin D3 metabolism.