Pituitary proopiomelanocortin peptides in mental disorders

Proopiomelanocortin (POMC) is a long-chain pituitary peptide (PP), the secretion of which is controlled by hypothalamic corticotropin-releasing factor (CRF). POMC is cleaved in the anterior pituitary (AP) into various fragments, including ACTH, β-lipotropin (β-LPH) and β-endorphin (β-E), which under physiological conditions are secreted concomitantly. Alterations in plasma levels of these peptides have been observed in mental disorders, but very few data have been obtained for parallel assays of all the fragments of POMC. In schizophrenia, it is observed that the untreated acute patients have lower basal levels of plasma β-E-like immunoreactive material than schizophrenics in remission and controls. The chapter reveals that no consistent relationship has been observed between PP impairment and any specific mental disorder, or any specific symptomatology in the context of a mental disorder. Therefore, impaired POMC derivative secretion by the pituitary may be, in some patients, not only the expression of a brain alteration, but may also influence, through feedback phenomena, the brain biochemistry and therefore the course and prognosis of the mental disease.