Biosynthesis and secretion of calcitonin in vitro in chicken ultimobranchial gland

Abstract Chicken ultimobranchial glands incubated in vitro in a defined medium containing 3 H-leucine synthesize and secrete calcitonin. The secretion was controlled by the Ca 2+ concentration of the medium over the range 0.63–5.0 m M , and it was stimulated by the addition of dibutyryl-adenosine 3′:5′ cyclic monophosphate. The cell homogeneity of chicken ultimobranchial gland makes this system more convenient than mammalian thyroid for studies on the biosynthesis and secretion of calcitonin.