title: Embryotropic effect of insulin-like growth factor (IGF)-I and its receptor on development of porcine preimplantation embryos produced by in vitro fertilization and somatic cell nuclear transfer.
abstract: Insulin-like growth factor (IGF)-I is a receptor-mediated autocrine/paracrine growth/survival factor for mammalian embryo development. The present study investigated the temporal expression and regulation of porcine IGF-I receptor (IGF-IR) mRNA and the role of IGF-I on development of porcine in vitro fertilized (IVF) and somatic cell nuclear transfer (SCNT) embryos. As assessed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), the level of IGF-IR mRNA expression was high in unfertilized oocytes, 2-cell and 4-cell embryos and gradually decreased in 8-cell embryos, morulae, and blastocysts in both IVF and SCNT series. The IVF or SCNT embryos were cultured with 0, 1, 10, 50, or 100 ng/ml IGF-I for 168 hr. Supplementing with 50 ng/ml IGF-I increased blastocyst formation and the number of cells in inner cell masses (ICMs) in both IVF and SCNT embryos. In a second experiment, more blastocysts were obtained when IVF or SCNT embryos were cultured for the first 48 hr or for the entire 168 hr with 50 ng/ml IGF-I compared to culturing without IGF-I for 48 hr or with IGF-I for the last 120 hr or without IGF-I for the entire 168 hr. Treating IVF or SCNT embryos with 50 ng/ml IGF-I significantly up-regulated IGF-IR mRNA compared to untreated control embryos. In conclusion, the present study demonstrated that IGF-IR mRNA is expressed in porcine IVF and SCNT embryos, and that IGF-I improved the developmental competence of IVF and SCNT embryos through its specific receptors.
authors.affiliation: Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.
authors.forename: Sue
authors.initials: S
authors.lastname: Kim
authors.forename: Gab Sang
authors.initials: GS
authors.lastname: Lee
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Hye Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Yeon Woo
authors.initials: YW
authors.lastname: Jeong
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Sung Keun
authors.initials: SK
authors.lastname: Kang
authors.forename: Byung Chun
authors.initials: BC
authors.lastname: Lee
authors.forename: Woo Suk
authors.initials: WS
authors.lastname: Hwang
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D046149:Embryo Culture Techniques; D005260:Female; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects* / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D053652:Nuclear Transfer Techniques; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1