Parathyroid hypertensive factor secretion from subcultured spontaneously hypertensive rat parathyroid cells

Cells dissociated from spontaneously hypertensive rat (SHR) parathyroid glands were grown in culture. Media harvested from the cell cultures were analyzed for parathyroid hypertensive factor (PHF) using the blood pressure bioassay. Cells raised in DMEM containing normal (1.8 mmol/L) CaCl₂ secreted a negligible amount of PHF, while cells cultured in Ham’s F-12 medium containing low (0.3 mmol/L) CaCl₂ secreted higher amounts of PHF. The PHF secretion in Ham’s F-12 medium was highest in early passage cells, and was maintained for approximately 12 to 15 passages. PHF purified from the cell culture medium exhibited chromatographic properties identical to those previously described for PHF isolated from SHR plasma or SHR parathyroid gland organ culture medium. These results support the parathyroid gland as the organ of origin of PHF.