[Disorders of hormone metabolism in chronic uremia]

Uremia is accompanied by a variety of "true" and "laboratory" endocrine disorders, due in part to impaired degradation of hormones because of failing kidney function and in part to the interference of the uremic environment with extrarenal degradation or synthesis and secretion of certain hormones. "True" endocrine disorders, like hyperparathyroidism or hypogonadism, that are associated with renal insufficiency are in contrast with "laboratory" endocrine disorders in uremia, where pathological serum hormone levels lack clearcut clinical evidence for dysfunction of the respective endocrine organ (e.g. thyroid gland). This lack of a direct cause and effect relationship in uremia may be due to the fact that immunoassayable hormone levels may include cross reacting components without biological activity in uremia and to the fact that the uremic environment may alter hormonal effects on target organs. This review tries to give a survey of the big amount of available clinical and laboratory data for uremia induced changes in the following hormones: growth hormone and somatomedins, prolactin, cortisol and adrenocorticotrope hormone, the gonadal and thyroid function as well as parathyroid hormone action. The knowledge of these uremia-induced changes should facilitate the clinician the diagnosis of an additional primary endocrine ailment in a uremic patient and should, on the other hand, spare these patients unnecessary treatment for a suspected endocrine disorder.