A senescent pattern of pituitary function during critical illness and dopamine treatment

Human critical illness is characterized by protein hypercatabolism, preservation of fat depots and by immune dysfunction. Optimized parenteral or enteral feeding and other advanced, supportive therapies remain unable to prevent ensuing wasting of vital organs and muscles and deficient healing processes. The anterior pituitary gland is a prime regulator of human metabolism and immune function through the orchestrated secretion of hormones, including growth hormone, thyrotropin, gonadotropins, prolactin and corticotropin. Except for the latter hormone, the releasing activity of the pituitary tends to decrease with advancing age and this decline is thought to be one of the mechanisms underlying the gradual loss of anabolic drive, reparative processes and cellular defence in senescence. In this work, critical illness was documented to be consistently associated with a diminished level of activity in the different axes governed by the pituitary, except for the corticotropic axis. In addition, this aging pattern of pituitary function in critical illness was found to be aggravated by the infusion of dopamine, a common practice in intensive care medicine for newborns, children and adults. The latter observation launches the hypothesis that endogenous dopamine may participate in the pathogenesis of the pituitary dysfunction in critical illness. Finally, these findings establish a base to explore the therapeutic potential of pituitary hormones and their secretagogues to enhance recovery from severe illness.