title: Characterization of the kallikrein-kinin system during the bovine ovulation process.
abstract: The kallikrein-kinin system (KKS) has been described as an important mediator of physiologic processes. Kallikreins use kininogen (KNG) as substrate to generate bradykinin, the main active peptide of the KKS that acts through two types of receptors, the B(1)R and the B(2)R. The goal of this study was to characterize some components of the KKS in different compartments of the ovary during the bovine ovulation process. The KNG, B(1)R and B(2)R mRNA expression patterns were assessed in theca and granulosa cells, as well as the bradykinin concentration and kallikrein-like activity in follicular fluid of bovine periovulatory follicles. To obtain a periovulatory follicle (≥12 mm), twenty-seven cows were submitted to estrus synchronization protocol and ovariectomized by colpotomy at 0, 3, 6, 12 or 24h after a GnRH-analog injection (gonadorelin; 100 μg, IM). Follicular fluid was aspirated for enzymatic assays while granulosa and theca cells were harvested for mRNA analysis. The mRNA expressions in follicular cells were evaluated by real-time RT-PCR and data representation related to the cyclophilin housekeeping gene. The bradykinin concentration and kallikrein-like activity were measured in follicular fluid by enzymatic immunoassay and selective substrate cleavage, respectively. The B(2)R expression in theca cells and B(1)R expression in theca and granulosa cells showed different profiles during the periovulatory period (P<0.05). The bradykinin concentration and kallikrein-like activity in the follicular fluid were different (P<0.05) due to the time during the ovulation process. KNG mRNA expression was similar for both follicular cell types (P>0.05). Taken together, these results provide an important characterization of the presence and possible KKS regulation during the bovine ovulation.
authors.affiliation: Programa de Pós-Graduação em Medicina Veterinária, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Gustavo Freitas
authors.initials: GF
authors.lastname: Ilha
authors.forename: Joabel Tonellotto
authors.initials: JT
authors.lastname: dos Santos
authors.forename: Alisson Minozzo
authors.initials: AM
authors.lastname: da Silveira
authors.forename: Karina
authors.initials: K
authors.lastname: Gutierrez
authors.forename: Camila de Campos Velho
authors.initials: Cde C
authors.lastname: Gewehr
authors.forename: Sara Marchesan
authors.initials: SM
authors.lastname: de Oliveira
authors.forename: Juliano
authors.initials: J
authors.lastname: Ferreira
authors.forename: Paulo Bayard Dias
authors.initials: PB
authors.lastname: Gonçalves
authors.forename: João Francisco Coelho
authors.initials: JF
authors.lastname: de Oliveira
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D006107:Granulosa Cells / Q000502:physiology; D006801:Humans; D016234:Kallikrein-Kinin System / Q000502:physiology*; D007610:Kallikreins / Q000235:genetics / Q000378:metabolism; D007704:Kininogens / Q000235:genetics / Q000378:metabolism; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology; D010053:Ovary / Q000166:cytology / Q000502:physiology; D010060:Ovulation / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043783:Receptor, Bradykinin B1 / Q000235:genetics / Q000378:metabolism; D043782:Receptor, Bradykinin B2 / Q000235:genetics / Q000378:metabolism; D013799:Theca Cells / Q000502:physiology
chemical_list: D007704:Kininogens; D012333:RNA, Messenger; D043783:Receptor, Bradykinin B1; D043782:Receptor, Bradykinin B2; D007610:Kallikreins