Histamine-induced hyperphosphatemia and hypocalcemia in the laying hen

The effects of histamine on plasma inorganic phosphorus (Pi) and total calcium values were studied in laying hens during egg formation and in non-laying hens. Histamine induced hyperphosphatemia and slight hypocalcemia during eggshell calcification, whereas the most pronounced hypocalcemia was observed during the early stages of egg formation. The histamine-induced hyperphosphatemia was completely inhibited by cimetidine but only partly by promethazine. However, the histamine-induced hypocalcemia was totally inhibited by cimetidine and promethazine.