Expression and localization of gap junctional connexins 26 and 43 in XXXX periovulatory follicles and in corpus luteum during different functional stages of oestrous cycle and pregnancy.

@entity2669 @entity73091 @entity1176 @entity13509 @entity291
The aim of this study was to characterize the regulation of connexins ( @entity73091 and @entity13509 ) in the @entity291 ovary (experiment 1-3). Experiment 1: ovaries containing preovulatory follicles or corpora lutea (CL) were collected at 0, 4, 10, 20, 25 (follicles) and 60 h (CL) relative to injection of @entity1176 . Experiment 2: CL were assigned to the following stages: days 1-2, 3-4, 5-7, 8-12, 13-16, >18 (after regression) of oestrous cycle and of early and late pregnancy (<4 and >4 months). Experiment 3: induced luteolysis, @entity291 on days 8-12 were injected with PGF2alpha analogue ( @entity2669 ), and CL were collected by transvaginal ovariectomy before and 0.5, 2, 4, 12, 24, 48 and 64 h after PGF2alpha injection. Real-time RT-PCR was applied to investigate mRNA expression and immunofluorescence was utilized for protein localization. @entity73091 mRNA increased rapidly 4 h after @entity1176 injection (during LH surge) and decreased afterwards during the whole experimental period. @entity13509 mRNA expression decreased continuously after @entity1176 application. @entity73091 mRNA in CL increased significantly in the second part of oestrous cycle and after regression. In contrast, the highest mRNA expression for @entity13509 in CL was detected during the early luteal phase. After induced luteolysis the mRNA expression of @entity73091 increased significantly at 24 h. As shown by immunofluorescence, @entity73091 was predominantly localized in the connective tissue and blood vessels of @entity291 CL, whereas @entity13509 was present in the luteal cells and blood vessels. This resulted in a strong increase of @entity73091 expression during the late luteal phase and after luteal regression. Subsequently, @entity13509 expression was distinctly decreased after luteal regression. These data suggest that @entity73091 and @entity13509 are involved in the local cellular mechanisms participating in tissue remodelling during the critical time around periovulation as well as during CL formation (angiogenesis), function and regression in the @entity291 ovary.
