Ethanol-Induced Hypocalcemia, Hypermagnesemia and Inhibition of the Serum Calcium-Raising Effect of Parathyroid Hormone in Rats1

Previously, we reported that ethanol produces a fall in total serum calcium in rats. In this study we show that the rapid (30 min) fall in total plasma calcium from 5 to 4.59 mEq⁄1 after a single oral dose of ethanol (6 g⁄kg) was ssociated with a significant (p < 0.001) fall in plasma ionic calcium from 2.78 to 2.55 mEq⁄1. The percent changes from controls in both total calcium and ionic calcium were similar, being approximately 8% each. A significant (p < 0.001-0.005) rise in serum magnesium also was observed at 3.5 and at 4 hr after alcohol administration. The hypermagnesemia associated with the hypocalcemia was demonstrated both with a single oral dose of alcohol (6 g⁄kg) and with repeated administration of a smaller dose (0.2 g⁄kg) every 0.5 hr for 2 hr (total dose = 0.8 g⁄kg). In acutely thyroparathyroidectomized rats, the effects of parathyroid hormone and alcohol on serum calcium were antagonistic. The data suggested that in intact rats the calcium-raising effect of the parathyroid hormone, secrete...