ABSTRACT

Membrane-bound cell surface peptidases can activate or inactivate biologically active peptides before peptide factors access to their receptors on the cell surface. In various human tissues, the expression   of aminopeptidase A (EC 3.4.11.7), placental leucine aminopeptidase (EC 3.4.11.3), aminopeptidase-N/CD13 (EC 3.4.11.2), dipeptidyl peptidases IV/CD26 (EC.3.4.14.5), carboxypeptidase-M (EC 3.4.17.12), neutral endopeptidase/ CD10 (EC 3.4.24.11) and endothelin converting enzyme-1 (EC 3.4.23) have been confirmed. These molecules are considered to play important roles in regulation of extracellular concentration of peptide factors. In reproductive system, ovarian and endometrial cells show dynamic changes including cellular growth, differentiation and regression during menstrual cycle and pregnancy. A number of biologically active peptides are known to regulate functions and/or differentiation of reproductive organs in an autocrine and/or paracrine fashion.  Cell surface peptidases are differentially expressed in the ovary, endometrium and placenta.  The inhibition of enzyme activity affects steroid hormone production by granulosa and thecal cells in the ovary, decidualization of endometrium and migration of extravillous trophoblasts at embryo implantation sites. Thus, membrane-bound  cell  surface peptidases can be  proposed to be important local regulators for cellular growth and differentiation in reproductive organs.