Kidney collecting duct principal cells are the main source of stanniocalcin-1 (STC-1) production and secretion. From there the hormone targets thick ascending limb and distal convoluted tubule cells, as well as collecting cell cells. More specifically, STC-1 targets their mitochondria to exert putative ant-apoptotic effects. Two distal tubule cell lines serve as models of STC-1 production and/or mechanism of action. MDCK-1 cells mimic collecting duct cells in their synthesis of STC-1 ligand and receptor, whereas IMCD-3 cells respond to additions of STC-1 by increasing their respiration rate. In the present study, MDCK cell STC-1 secretion was examined under normal and hypertonic conditions, vectorally, and in response to hormones and signal transduction pathway activators/inhibitors. STC-1 receptor regulation was monitored in both cell lines in response to changing ligand concentration. The results showed that sodium chloride-induced hypertonicity had concentration-dependent stimulatory effects on STC-1 secretion, as did the protein kinase C (PKC) activator, TPA. Calcium and ionomycin were inhibitory, whereas calcium receptor agonists had no effect. Angiotensin II, aldosterone, atrial natiuretic factor, antidiuretic hormone and forskolin also had no effects. Moreover, STC-1 secretion exhibited no vectoral preference. STC-1 receptors were insensitive to homologous downregulation in both cell lines. In contrast, they were upregulated when STC-1 secretion was inhibited by calcium. The findings suggest that hypertonicity-induced STC-1 secretion is regulated through PKC activation and that high intracellular calcium levels are a potent inhibitor of release. More intriguingly, the results suggest that that the receptor may not accompany STC-1 in its passage to the mitochondria.