In the current study, follicular development was associated with a decrease in intensity or a complete loss of type IV collagen chains from the follicular basal lamina. Additionally, staining for a1(IV) and a2(IV) was frequently unevenly distributed along the follicular basal lamina of antral follicles, being present in some areas and absent in others. Conversely, in our previous study of laminin chains, the intensity of staining increased with increasing follicle size. Thus there appears to be a transition from a type IV collagen-rich to a laminin-rich follicular basal lamina with increasing follicle size. buy yasmin online
Type IV collagen molecules can be covalently cross-linked to form a much more rigid network than the laminin network, and absence or discontinuity of the type IV collagen network might reflect the need for active basal lamina expansion during follicular development. It has been calculated that the surface area of the bovine follicle, the area covered by the follicular basal lamina, increases some 317 400-fold or doubles 19 times in developing from the primordial follicle stage to the 18-mm preovulatory-sized follicle.