[Lipotropins (beta- and gamma-LPH). Valid indicators of corticotropic function].

Plasma levels of ACTH and LPH which derive from a common precursor, were determined simultaneously to study the value of LPH as a marker of the corticotropic function, and evaluate its advantage over that of ACTH plasma determination. ACTH and LPH plasma levels were measured: a) in control subjects under basal conditions and after dynamic explorations of the corticotropic axis. Furthermore, in some control subjects plasma LPH levels were measured after a 24 h incubation in blood at room temperature; b) in the venous and arterial blood of the kidney of subjects in whom a nephrectomy of a perfused and functional kidney was to be performed; c) in patients either under hemodialysis for chronic renal failure, or with adrenal insufficiency due to a primary adrenal failure or secondary to a corticotropic deficiency. This study permitted to establish: a) the normal values of basal plasma hormone levels (ACTH less than 10-80 pg/ml, LPH less than 20-200 pg/ml 8-9 a.m.) and to confirm their parallel secretions in physiological conditions; b) the stability of the LPH in blood at room temperature, whereas ACTH is rapidly destroyed in the same conditions; c) the primordial role of the kidney in the LPH catabolism; d) the value of LPH determinations in the diagnosis of primary adrenal insufficiency and corticotropic deficiency. Thus, except for the known situations where ACTH and LPH plasma levels are dissociated, the LPH plasma levels either basal or after dynamic explorations of the corticotropic axis, provide a reliable index of the corticotropic function.