The effects of dopamine administration on the adrenal gland of a lizard, Podarcis sicula, are described. Dopamine (0.7 mg/100 g body wt/day for 4 consecutive days) raised plasma ACTH and corticosterone levels (ACTH: from the basal level of 4.40 ± 0.05–7.30 ± 0.08 pg/ml 24 h after the fourth dopamine injection; corticosterone: from 3.59 ± 0.03 ng/ml in untreated lizards to 7.40 ± 0.05 ng/ml 24 h after the fourth dopamine injection), showing a stimulatory effect on the pituitary-interrenal axis activity. In the chromaffin tissue dopamine apparently enhanced the activity of PNMT enzyme; in fact a strong raise in the number of adrenaline cells and a decrease in the number of noradrenaline cells were observed, decreasing the numeric NA/A cell ratio, from 1.4/1 of control specimens to 0.5/1 24 h after the fourth dopamine injection. At EM level, chromaffin cells contained both NA and A granules, as well as very clear granules (CG); CG granules showed granular elements ranging between 340 and 347 Å in diameter. These cells might be the morphological expression of a process of catecholamine resynthesis, due to a possible increase in catecholamine release, following exposure to dopamine.