Embryo

The Beneficial Effects of Insulin and Metformin on In Vitro Developmental Potential of Porcine Oocytes and Embryos

Abstract
In order to investigate whether insulin and/or metformin improve the developmental competence of porcine oocytes and embryos, insulin (100 ng/ml) and/or metformin (10^-5 M) were supplemented during in vitro maturation (IVM) and/or in vitro culture (IVC) period. Insulin (33 to 34% vs. 21%) or insulin plus metformin (27 to 39% vs. 21%) significantly (P < 0.01) increased the rates of blastocyst formation, while metformin alone had no effect when added during the first half (0-22 h), the latter half (22-44 h) or the entire (0-44 h) maturation period. No additional effect of insulin plus metformin on increasing blastocyst formation was observed compared to insulin alone. When supplemented during IVC, insulin (34% vs. 23%) or insulin plus metformin (35% vs. 23%) significantly (P < 0.05) increased the rates of blastocyst formation, while metformin alone had no effect. Compared to insulin alone, no additional effect of insulin plus metformin on increasing blastocyst formation was observed. When added during the entire IVM and IVC, insulin (40% vs. 24%) or insulin plus metformin (52% vs. 21%) significantly increased the rates of blastocyst formation, while metformin alone had no effect. In addition, the effect of insulin was enhanced when supplemented with metformin compared to insulin alone (52% vs. 40%). After IVM, oocyte glutathione (GSH) content and tyrosine kinase activity were measured. Insulin significantly (P < 0.01) increased oocyte GSH content (6.2 pmol vs. 4.3 pmol) and metformin significantly (P < 0.01) enhanced the action of insulin on GSH content (7.3 pmol vs. 6.2 pmol) and tyrosine kinase activity (1.9 arbitrary unit [AU] vs. 1.5 AU) when compared to insulin alone. In conclusion, insulin increased the developmental potential of porcine oocytes and embryos, and metformin enhanced the action of insulin when supplemented during the entire IVM and IVC. The effects of insulin and metformin were associated with oocyte GSH content and tyrosine kinase activity.

Key words: Embryo • Gamete Biology • In vitro fertilization • Insulin • Ovum

This article has been cited by other articles:

				L. Tosca, C. Chabrolle, S. Uzbekova, and J. Dupont Effects of Metformin on Bovine Granulosa Cells Steroidogenesis: Possible Involvement of Adenosine 5' Monophosphate-Activated Protein Kinase (AMPK) Biol Reprod, March 1, 2007; 76(3): 368 - 378. [Abstract] [Full Text] [PDF]

				E. Elia, V. Sander, C.G. Luchetti, M.E. Solano, G. Di Girolamo, C. Gonzalez, and A.B. Motta The mechanisms involved in the action of metformin in regulating ovarian function in hyperandrogenized mice Mol. Hum. Reprod., August 1, 2006; 12(8): 475 - 481. [Abstract] [Full Text] [PDF]