We have recently shown that not only
bradykinin, but also all components for the production of
bradykinin, can be detected within the follicle of porcine ovaries. To elucidate the relevance of the intrafollicular
bradykinin-producing system to its physiological role, we investigated the distribution of
bradykinin receptor (
B(2)R)
mRNA and the
protein in porcine ovaries. A
cDNA encoding porcine
B(2)R was first cloned from a porcine uterus cDNA library. The receptor
mRNA was scarcely detected in the ovary by Northern blot analysis. Polymerase chain reaction analysis with total RNAs isolated from the ovary and from granulosa cells of small and large follicles demonstrated the ovarian expression of
B(2)R
mRNA. The
B(2)R
protein was detected by Western blot analysis in extracts of isolated granulosa cells. In situ hybridization of
B(2)R
mRNA and immunohistochemical analysis of the
protein revealed that the receptor is expressed in the theca and granulosa cells of all growing follicles. The effect of
bradykinin on the expression of some
matrix metalloproteinase (
MMP) genes was examined using isolated granulosa cells.
Bradykinin treatment induced MMP-3 and MMP-20 gene expression to an extreme degree. The expression of
MT1-MMP was also affected by
bradykinin treatment. These results suggest that
MMPs play a role in follicle
rupture during ovulation. The present study provides new information regarding the mechanisms of
bradykinin-induced ovulation in porcine ovaries.