Influence of Gossypol on Testosterone Secretion from Leydig Tm3 Cells under Hypoxia

Gossypol is a natural polyphenolic compound extracted from the cotton plant (Gossypium arboretum Linn.). Gossypol has been known to as a potential male contraceptive agent. Studies indicated that gossypol reduces sperm number, inhibits spermatogenesis, and decreases plasma and media testosterone concentration in human being and other mammalian animals. Oxygen is the most basic element necessary for all eukaryotic life. Insufficient oxygen (hypoxia) deprives the respiratory chain of its main electron acceptor. Hypoxia inducible factor 1 alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF) play an important role in promoting tumor progression. However, the effect of gossypol on testosterone (T) secretion from Leydig cells are still unknown, especially in a hypoxia condition. The purpose of this study will conduct the influence of gossypol on Leydig TM3 cells by analysis the secretion of T under normoxia and hypoxia. The hypothesis applied in this study is that gossypol may affect the secretion of T from TM3 cells through the regulation of HIF-1 alpha, MAPK, sirtuins (Sirt1 and Sirt2), COX-2, and VEGF expressions in hypoxia condition. Therefore, the specific aim for this study is to analyze if the effect of gossypol on TM3 under hypoxia (1% O2) is through HIF-1 alpha, VEGF, MAPK, Sirt1 and Sirt2, and COX-2 expression and compared to normoxia condition (21% O2). Media T levels will be measured by enzyme-immunoassay (EIA). Western blot will be applied for protein expression of HIF, VEGF, Sirt1/2, and COX-2. Preliminary data showed that hypoxia induced significant increased T level and HIF-1 alpha,-2 alpha, and VEGF expression in TM3 cells. Significant decreased media T level and HIF-1 alpha expression were observed in TM3 cells with different concentrations of gossypol under hypoxia. We hope these experiments will provide relevant information for the understanding of influence of gossypol on Leydig cells function under hypoxia condition.

Project ID:PB10708-1742
External Project ID:MOST107-2320-B182-001