DENDRITIC CELLS AND MACROPHAGES IN THE PITUITARY AND THE GONADS - EVIDENCE FOR THEIR ROLE IN THE FINE REGULATION OF THE REPRODUCTIVE ENDOCRINE RESPONSE

Blood monocytes are able to mature into macrophages as well as into de ndritic cells, Dendritic cells and macrophages have mainly been studie d for their function in the immune response, e.g. in the presentation of antigens to lymphocytes and in the phagocytosis/degradation of unwa nted material. The cells are also, however, important producers of a v ariety of signalling molecules and hormones and are thus involved in o ther physiological functions such as wound healing, the regulation of the microcirculation and the regulation of the function and growth of endocrine cells, This review summarizes the existing evidence for a re gulatory role of dendritic cells and macrophages in the function and g rowth of hormone-producing cells of the pituitary-gonadal axis. It foc usses on the presence, localization and phenotype of dendritic cells a nd macrophages in the anterior pituitary and the gonads, the endocrine regulatory role of cytokines produced by these cells and the existenc e of putative feedback mechanisms between endocrine cells of the pitui tary-gonadal axis and dendritic cells and macrophages. The recognition of a 'floating endocrine-regulatory force' of monocyte-derived cells that also plays a role in the initiation of immune responses has impli cations for our understanding of the pathogenesis of gonadal and pitui tary autoimmune reactions.