The presence of extra-pituitary prolactin and its cognitive receptors in the hematopoietic micro-environment raises the question of whether prolactin plays a role in lympho-hematopoiesis and under what conditions. Current studies suggest that endogenous prolactin does not play a signifycant role under normal steady-state conditions. Rather, prolactin has been implicated as a `stress hormone', functioning to restore hematopoietic homeostasis under conditions of dysregulation. The stress response of prolactin as well as its complex relationship with other hormones and factors has resulted in confiicting reports in the literature regarding prolactin's role in lympho-hematopoiesis. A review of this literature is provided as well as discussion of conditions under which lymphohematopoietic activity of prolactin may be evident. Lupus (2001) 10, 700±705.
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