Immunochemical characterization and distribution of calcitonin in the lizard.

Immunological and chromatographic methods were used to investigate the distribution of calcitonin (CT) in various tissues of Lacerta muralis, a common wall lizard. Salmon CT-like immunoreactivity was found in high concentration in extracts of ultimobranchial gland (UBG) and in significant amounts in lung and brain extracts, but not in other tissues (oesophagus, stomach, duodenum, liver, skin, muscle and thyroid). Serial dilution of UBG, lung and brain extracts gave parallel displacement curves to that of synthetic salmon CT (sCT), but no reactivity was found in the human CT assay. On Sephadex G-50, UBG, lung and brain extracts contained an sCT-like immunoreactive peak which co-eluted with synthetic sCT. However, on high performance liquid chromatography (HPLC) the sCT-like peak in UB, lung and brain extracts eluted 2 ml later than synthetic sCT. This paper describes the first immunochemical characterization of CT in the UBG of the lizard, demonstrates the distribution of extra-ultimobranchial CT and throws some light on the evolution of the calcitonins.