The hypocalcaemic and hypophosphataemic effect of extracts from chicken ultimorbranchial glands

Acid extracts of chicken ultimobranchial and thyroid glands were assayed in the rat for their effects on serum calcium and phosphate. The concentration of a hypocalcaemic factor in the ultimobranchial tissue was more than 100 times greater than that found in pig thyroid tissue. No hypocalcaemic activity was found in the chicken thyroid gland. An extract of the ultimobranchial glands was found to have a significant hypophosphataemic effect in the rat. This fact combined with the parallelism of the log dose-response curves found for the ultimobranchial gland extract and a calcitonin standard, suggests that hypocalcaemic factor is similar to mammalian calcitonin.