Characterization of the Kinin System in the Ovary during Ovulation in the Rat1

Abstract

Ovulation has been noted for some time to bear a remarkable similarity to an inflammatory response. One of the principal components that is activated and helps mediate the events during an inflammatory response is the kinin system. Therefore, the purpose of the present study was to examine whether this system could be similarly activated and involved in the cascade of events that leads to ovulation. To answer this question, immature 23-day-old female rats were primed with eCG (10 IU) and ovulation was induced by administration of hCG (10 IU) 48 h later. Groups of rats were killed at 0 h, 10 h, 20 h, and 30 h after hCG for determination of ovulation, ovarian steroid levels, and changes in the levels of kinin system components. Plasma total kininogen levels did not change during the entire period studied. In contrast, ovarian total kininogen levels rose from 0 h to reach a peak at 10 h--a time immediately preceding the beginning of ovulation--after which the levels fell at 20 h, only to rise again at 30 h. Three species of kininogens, high molecular weight (HMW), low molecular weight (LMW), and T-kininogen, were shown to be present in the ovary. T-kininogen was the major kininogen present in the ovary, accounting for 60-92% of the total kininogen at any given time point during the ovulatory process. HMW kininogen levels accounted for only 1.2% of the total ovarian kininogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of Components of the Intrafollicular Bradykinin-Producing System in the Porcine Ovary1

“…Previous studies have demonstrated an increase in ovarian kinin-producing activity during ovulation [27][28][29]. Moreover, it has been established that BK induces ovulation in perfused rabbit ovaries [30][31][32] and potentiates the action of LH [33].…”

“…This points to the possibility that intrafollicular kallidin (lysyl-BK) might also be produced from LMW-K. A tissue kallikrein is generally thought to catalyze the production of kinin from LMW-K. Several investigators have indeed reported an increase in tissue kallikrein activity [27][28][29]34] with a concomitant elevation of LMW-K [28] in rat ovary extract during ovulation. At present, however, it is not known to what extent the LMW-K/tissue kallikrein system contributes to kinin formation within porcine ovarian follicles.…”

Detection of Kallikrein Gene Expression and Enzymatic Activity in Porcine Endometrium During the Estrous Cycle and Early Pregnancy1

“…Kallikrein is an active member in the kininogen-kallikreinkinin (K-K-K) system in which kallikrein cleaves kininogen to release the vasoactive peptide, bradykinin [12]. The K-K-K system has been shown to be involved in reproductive functions such as ovulation [13] and implantation in the rat [14]. Corthorn and coworkers [15] demonstrated that estrogens play a role in stimulating kallikrein release.…”

Localization of gonadotrophin-releasing hormone I, bradykinin and their receptors in the ovaries of non-mammalian vertebrates

“…This suggests that bradykinin acts directly on GnRH neurons through a mechanism involving mediation by the bradykinin B 2 receptor. It has already been reported that kinin-producing activity increases during ovulation (Smith & Perks 1983, Espey et al 1989, Gao et al 1992. In a study, Kihara et al (2000) showed the presence of a component of bradykinin and bradykinin-producing system in the porcine ovarian follicle, suggesting its role in early follicular development and ovulation.…”