The physiological role of tyreoliberyny ( TRH ) is to maintain homeostasis within the four systems: ( i) the neuroendocrine hypothalamus -pituitary gland, (ii ) neuronal pathway brainstem - midbrain - spinal cord, ( iii ) the limbic - cortical and (iv ) the chronobiologic. In this way, TRH through different cellular mechanisms regulate many biological processes ( general stimulation of the body , sleep , learning, lokomotorykę mood ) and can be considered for intervention and clinical use in the event of disturbance in the individual systems .

Activating polypeptide Pituitary adenylate cyclase ( PACAP ) and vasoactive intestinal peptide (VIP) belong to a family of polypeptide hormones which include representatives glucagon, secretin and growth hormone releasing hormone . PACAP and VIP are widely distributed in both the central nervous system and in peripheral tissues of various vertebrates . PACAP exists in two forms : parent , 38 - amino acid form ( PACAP38 ) and shorter 27 - amino acid form ( PACAP27 ) . PACAP27 has 68 % sequence identity with VIP consisting of 28 amino acids.