title: Insulin regulates primordial-follicle assembly in vitro by affecting germ-cell apoptosis and elevating oestrogen.
abstract: Insulin is a protein secreted by pancreatic β-cells, which plays an important role in the regulation of ovarian function. However, the specific molecular mechanism of its function remains largely unknown. This study aimed to assess the effect of insulin on mouse folliculogenesis using an in vitro ovary-culture model. The results demonstrated that insulin promoted the proliferation of ovarian granulosa cells in vitro, and thereby accelerated the progress of folliculogenesis (the percentage of oocytes in cysts declined from 42.6% to 29.3%); however, the percentage of apoptotic oocytes increased after insulin treatment. Further investigation indicated that apoptosis occurred mainly in germ-cell cysts. After 3 days of insulin treatment, oestrogen in the culture medium of mouse ovaries significantly increased (P<0.01), while the lower dose of oestrogen promoted primordial-follicle assembly in vitro. In conclusion, insulin promoted folliculogenesis by facilitating germ-cell apoptosis within the cysts and upregulating oestrogen levels.
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Xin-Lei
authors.initials: XL
authors.lastname: Feng
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Yuan-Chao
authors.initials: YC
authors.lastname: Sun
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Shun-Feng
authors.initials: SF
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Yan-Ni
authors.initials: YN
authors.lastname: Feng
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Jing-Cai
authors.initials: JC
authors.lastname: Liu
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Wang
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Li
authors.affiliation: EMF Nutrition, 715 Marion Street, Winnipeg, Manitoba, R2J 0K6, Canada.
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Qin
authors.affiliation: Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003470:Culture Media / Q000737:chemistry; D004958:Estradiol / Q000032:analysis*; D005260:Female; D005854:Germ Cells / Q000187:drug effects* / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D051379:Mice; D009924:Organ Culture Techniques; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism; D010053:Ovary / Q000187:drug effects / Q000378:metabolism
chemical_list: D003470:Culture Media; D007328:Insulin; D004958:Estradiol