This thesis examined the effects of equine relaxin (ERXN) on proliferation of equine ovarian stromal cells (EOSC), the production of gelatinase A (MMP-2) and gelatinase B (MMP-9), tissue inhibitors of matrix metalloproteinases (TIMPs), urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) by EOSC in vitro. Equine ovarian stromal cells were isolated from stroma at the apex of growing follicles. Equine relaxin inhibited \sp3H-thymidine incorporation by EOSC and decreased proliferation. Equine relaxin stimulated the production of gelatinase A, gelatinase B, uPA and tPA. Equine relaxin also stimulated the production of TIMP-1, TIMP-2, and PAI-1. Evidence is presented that ERXN performs its effects in a paracrine manner in equine ovary. Equine relaxin contributes, in part, to the connective tissue remodeling required for equine follicle growth by inhibiting the proliferation of stromal cells, by stimulating gelatinases and plasminogen activators and by stimulating production of TIMP-1, TIMP-2 and PAI-1 to prevent excessive extracellular matrix degradation. Transforming growth factor-β and phorbol 12-myristate 13-acetate were found to influence EOSC activity and modulate the production of gelatinases A and B. TIMP-1 TIMP-2, uPA, tPA and PAI-1. 13-acetate were found to influence EOSC activity and modulate the production of gelatinases A and B, TIMP-1 TIMP-2, uPA, tPA and PAI-1.