Expression Of Inhibins And Brain-derived Neurotrophic Factor In Porcine Follicles

Inhibin is a gonadal hormone which is composed of an α-subunit and one oftwo related-subunits (A, B). Inhibin is important for pituitary FSH regulation.Neurotrophins, a family of growth factor, are not only required for the survival anddifferentiation of the nervous system but also important for the development ofmammalian reproductive tissues. Experiments were conducted to examine theexpression of inhibins and neurotrophins in porcine ovarian follicles from small (<3mm), medium (3-6mm) and large size (>6mm), which were obtained in follicularand luteal phases. This study identified the expression of inhibin α, inhibin A,inhibin B and BDNF mRNAs and proteins. The presense of target genes wasinvestigated by using RT-PCR and Western blotting, qPCR and ELISA assay wereemployed to determine expression levels of each gene. By employing the RT-PCRtechnique and Western blotting, the study demonstrated that the inhibin α, inhibinβ A, inhibin B and BDNF mRNAs and proteins were expressed in small, medium andlarge follicles both of follicular and luteal phases. The amount of inhibin α, inhibinβA, inhibin B and BDNF mRNAs expressed in medium follicles was greater thanthose in small and large follicles (P<0.01). Inhibin α, inhibin A, inhibin B andBDNF protein expression levels in different diameter follicles were determined incomparison with-actin level as control protein. The highest levels were found inmedium follicles both of follicular and luteal phases. The concentrations of inhibin A(α-A) and inhibin B (α-B) in follicular fluid from medium and large follicleswere lower than those from small follicles (P<0.05). In contrast, the concentration ofBDNF in follicular fluid from medium follicles was greater than that from small andlarge follicles (P<0.05). The data indicated that inhibins and BDNF express ingranulosa cells at different stages of estrous cycle of sows. This study may stronglyaid in understanding the potential roles of inhibin α, inhibin A, inhibin B andBDNF in the mammalian reproductive mechanism.