Chromaffin Tissue in the Lizard Adrenal Gland

BOTH adrenaline and its possible precursor nor-adrenaline can be obtained from the adrenals of many animals in the different classes of vertebrates¹. In the dogfish, where adrenocortical and chromaffin tissue are entirely separate, the latter contains wholly noradrenaline². In the Amphibia, where the two tissues are intermingled, noradrenaline forms 50-69 per cent of the total catechol content in the frog² and 35-58 per cent in the toad³. In the eutherian mammal, chromaffin tissue, formed as a medulla surrounded by cortical tissue, produces mostly adrenaline^1,2,4.