POMC and hypothyroidism: In rats, hypothyroidism over the perinatal period also decreases the expression of components of the hypothalamic-pituitary-adrenal (HPA) axis and ACTH and glucocorticoid secretion (Dakine et al., 2000), although the relative contribution of suppressed glucocorticoid activity to the gastrointestinal abnormalities seen in models of fetal or neonatal hypothyroidism is unknown.