Expression of follicle-stimulating hormone receptor (FSHR), protein kinase B-2 (AKT2) and adapter protein with PH domain, PTB domain, and leucine zipper (APPL1) in pig ovaries.

Follicle-stimulating hormone (FSH) regulates oogenesis and spermatogenesis by binding to its receptor (FSHR) on target cells in the ovary and testis, respectively. The signaling cascades activated after ligand binding are extremely complex and have been shown to include protein kinase A and phosphatidylinositol 3-kinase/protein kinase. The adapter protein APPL1 (adapter protein with PH domain, PTB domain, and leucine zipper), which is an assortment of other signaling proteins, was previously identified to interact with the FSH receptor (FSHR) and the protein kinase B (AKT) pathway. APPL1 plays an important role in promoting cell survival within the preovulatory follicle granulosa layer. Here, we aimed to evaluate the FSHR, AKT2, and APPL1 gene and protein expression levels in the ovaries of different prolific porcine breeds (Wannan Black [WB] and Large White [LW] pigs) using immunohistochemistry and qRT-PCR, respectively. Our results showed that FSHR, AKT2, and APPL1 mRNA levels were significantly higher (P < 0.05) in the ovaries of WB pigs than in the ovaries of LW pigs. Additionally, the FSHR, AKT2, and APPL1 proteins were mainly found distributed in the granulosa cells and oocytes. This study showed that high levels of FSHR, AKT2, and APPL1 were expressed in the ovaries of high prolific breed pigs.