Cadmium Induces Apoptosis in the Pituitary Gland of Podarcis sicula

The cytotoxic effects of cadmium (Cd) on the pituitary gland were studied in the lizard Podarcis sicula. Adult lizards were treated intraperitoneally with a single injection of CdCl2 at the dose of 2 mg/kg. A morphological study was performed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technique and by immunocytochemical demonstration of caspase-3 for detecting apoptotic cells in situ after 2, 7, and 16 days of treatment. The pituitary cells of Cd-treated P. sicula undergo apoptosis: after 2 days the apoptotic cells appeared to increase significantly compared with those of the control specimens; after 7 days there was no considerable increment; however, after 16 days the occurrence of apoptotic cells had increased markedly, above all in the rostral pars distalis (RPD) in which various cells showed a strongly immunostained nucleus by TUNEL. Cd appears particularly toxic for pituitary cells in the lizard P. sicula; a single high intraperitoneal dose of CdCl2 induces apoptosis, in particular in the RPD, and this effect appears irreversible.