Presence of met-enkephalin in bovine pituitary intraglandular colloid of intermediate lobe origin

Met-enkephalin, and opioid peptide present in the intermediate lobe of the pituitary gland, is herein demonstrated, for the first time, in bovine pituitary intraglandular colloid. Colloid samples were taken from the glands of freshly slaughtered cattle, pooled, lyophilized, extracted on octadecylsilyl-silica and assessed by radioimmunoassay. Met-enkephalin was indeed present in this colloid extract at levels varying from 0.40 to 0.85 nanograms …