Potassium Stimulates Parathyroid Hormone Release from Perifused Parathyroid Cells*

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Abstract
A method for perifusing dispersed bovine parathyroid cells is described. Using this approach, we have studied the effects of raised extracellular potassium and ouabain on calcium-regulated parathyroid hormone (PTH) secretion in vitro. Decreasing calcium from 1.5 to 0.5 mM stimulated PTH release within 5–10 min, and the increased secretory rate was maintained for the duration of the low calcium administration. High potassium (60 mM) promptly stimulated PTH secretion at 1.5 mM calcium. The effect of high potassium was more transient than that of low calcium. Raised potassium significantly enhanced the response to 0.5 mM calcium. Ouabain (10-3 M) had no significant effect at 1.5 mM calcium, but depressed the secretory response to 0.5 mM calcium. In conclusion, the effect of raised potassium on parathyroid cells is qualitatively similar to its effect on other endocrine and exocrine systems.