Coexistence of hypothalamic factors with other neuropeptides. Demonstration in the median eminence of rats and guinea-pigs.

Using immunohistochemical methods at the light and electron microscope level, the coexistence between a hypophysiotropic factor and an apparently unrelated neuropeptide was demonstrated in three distinct infundibular neuronal systems. The present results emphasize the importance of demonstrating peptide coexistences for a better understanding of the regulating mechanisms in neuroendocrinology.