The multiplicity of genes regulated by the actions of LH in specific granulosa cell and cumulus cell microenvironments of the follicle during ovulation has now revealed how complex and finely tuned the ovulation process is. Although many proteases are expressed in the ovary and are hormonally regulated, the novel proteases ADAMTS-1 and cathepsin L, rather than the MMPs, have gained particular recognition. These may play critical roles in the eventual rupture of the follicle at the ovarian surface. Rupture is only one part of ovulation. Another important aspect is the actual release of the oocyte from the ovulation pore. Several recent studies have shown that the production of the matrix that is evidenced by cumulus expansion is somehow critical for extrusion to occur and for the oocyte to travel into the oviduct. At any point the oocyte may be trapped within a non-ovulating structure. Lastly, if the events of ovulation fail to occur before the events of luteinization are complete, oocytes are destined to degenerate within the non-ovulating structures.