Non-secretory neuronal elements in the bovine pituitary intermediate lobe

The bovine pituitary intermediate lobe was studied by light microscopy after staining with a modified Bodian procedure. The study revealed a number of dissimilar intermediate lobe elements characteristic of mature and immature cells found in the adult and embryonic central nervous system and ganglia. In this study the elements are referred to as non-secretory neuronal elements. The elements, forming part of the parenchyma, have multiple processes which distribute themselves throughout the lobe. The typical secretory intermediate lobe cells have only a slight affinity for the Bodian stain. The intermediate lobe basophilic staining secretory cells and the neuronal elements maintain their general differences in appearance and possibly their function. Since the intermediate lobe in bovine is rather avascular and neuronal elements are usually associated with blood vessels, these elements may be involved in certain mechanisms yet unknown. It is possible that the elements provide common precursor proteins that reach the secretory intermediate lobe cells through their dendritic branches. In addition, the non-secretory neuronal elements may be directly involved in the spike potentials recorded from the lobe as well as in stimulus-secretion coupling. This study does not treat the function of the neural elements at this time, but directs attention strictly to their presence in the intermediate lobe of the bovine pituitary gland.