Histochemical distribution of endothelin-converting enzyme subtypes in Podarcis sicula (Squamata, Lacertidae) tissues

The distribution of endothelin-converting enzyme (ECE) in the lizard Podarcis sicula was investigated immunohistochemically using antibodies against endothelin-converting enzyme ECE-1 and endothelin-converting enzyme ECE-2 homologues. In all the tissues examined, immunoreactivity for both antibodies was found, although the distribution and degree of expression varied. Strong immunoreactivity was found in the endothelial cells and chromaffin tissue for both enzymes, whereas other tissues such as nervous tissue, renal tissue and hepatocytes display distinct patterns. Current knowledge does not allow correlation of these distribution patterns to specific functions but the data suggest that, in reptiles as in mammals, ECE is probably involved in physiological functions such as paracrine activity through endothelins and/or other substrates.