Co-existence of glicentin and peptide YY in colorectal L-cells in cat and man. An electron microscopic study.

Electron microscopic immunocytochemistry using protein A-gold labelling of ultrathin sections revealed immunoreactive glicentin (gut-type glucagon) and peptide YY (PYY) in virtually all secretory granules in a population of L-type endocrine cells in feline colon and human rectum. The granules of the human glicentin/PYY cells were considerably smaller in size than those in the cat. In both species the results indicate co-existence of glicentin and PYY in the same secretory granules, despite the probable derivation of the two peptides from two different precursors.