Effect of Insulin-Like Growth Factors (Igfs) and Igf-Binding Proteins on in Vitro

• Main Authors: Miao, Z. R., LIN, Ting Kwong, Bongso, T. A., Zhou, X., Cohen, P, KO, Lee
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 1998
• Subjects: Econometrics; Medicine and Health Sciences
• Online Access: https://ink.library.smu.edu.sg/soe_research/267
• Institution: Singapore Management University

Previous studies have shown that exogenous growth hormone (GH) produces increases in sperm motility when given to subfertile men. Previous studies have also demonstrated the presence of IGFs and IGFBPs in seminal plasma. We have therefore investigated the effects of insulin-like growth factor-I (IGF-I), IGF-II, IGF-binding protein 2 (IGFBP-2) and intact IGFBP-3 on in vitro sperm motility. DESIGN AND METHODSUsing computer-aided sperm analysis, we investigated the effects of IGFs and IGFBPs on the in vitro sperm motility parameters: curvilinear velocity (CV), progressive velocity (PV), linearity (Ln), straightness (St), amplitude of lateral head movement (ALH), and beat frequency (BF). Washed motile sperm selected by the ‘swim-up’ method, from normozoospermic samples, were incubated at 37°C in 5% CO in air with IGF-I, IGF-II, IGFBP-2, IGFBP-3, or control Earle's media, and were examined at time 0 and after 60 min incubation. Changes in motility parameters after 60 min incubation were compared with controls by analysis of variance (ANOVA). RESULTSCompared to controls, statistically significant changes occurred at time 60 min after incubation: IGF-I decreased CV and ALH significantly (P < 0.05), but IGFBP-3 increased Ln, St, BF, and decreased ALH significantly (P < 0.05). In contrast, IGF-II, IGFBP-2, and a combination of IGF-I/IGFBP-3, had no significant effects. CONCLUSIONSIGF-I and IGFBP-3 have differing and opposing effects on in vitro sperm motility parameters and thus may have a role in modulating in vivo sperm motility.