Role of antipituitary antibodies in the pathogenesis of hyperprolactinemia

Abstract

For evaluating the probable role of autoimmune disorders in the pathogenesis of hyperprolactinemia, humoral immunity parameters (antibodies to surface antigens of adenohypophysis cells - ASAG - and to prolactin - Prl) were studied in 26patients with idiopathic hyperprolactinemia (group 1), 32 with prolactinomas (group 2), and 12 pregnant women with physiological hyperprolactinemia (group 3). Using rat adenohypophysis and human prolactinoma cells, respectively, ASAG were detected in 38.5- 76.9% patients in group 1, IS. 7-29% in group 2, and in none of the women in group 3. The predominance of ASAG-positive patients in the idiopathic hyperprolactinemia group in comparison with prolactinoma patients was statistically significant (p < 0.001). Using lactotrophs instead of rat adenohypophysis cells, ASAG were also detected significantly more often in the patients with idiopathic hyperprolactinemia (p = 0.11). The presence of antibodies to Prl in the overwhelming majority of patients did not coincide with the presence of ASAG, which means that ASAG and autoantibodies to Prl are different antibody types. The presence of antibodies to surface lactotroph antigens detected in many patients of group 1 suggests that autoimmune disorders can be one of the causes of idiopathic hyperprolactinemia.