Effect of hypoxia on the release of vascular endothelial growth factor and testosterone in mouse TM3 Leydig cells

Abstract

Hypoxia has been shown to stimulate the expression of vascular endothelial growth factor (VEGF), which is a major mediator for angiogenesis and vasculogenesis. During hypoxia, VEGF promotes angiogenesis in the testis. However, the effect of VEGF on the steroidogenesis of testosterone and the cell proliferation in Leydig cells is unclear. To assess the effects and the action mechanisms of hypoxia, a mouse TM3 Leydig cell line was employed in the present study. The Leydig cells were incubated in an incubator chamber (95% N2-5% CO2) for 1–24 h. The cultured media were collected and assayed by testosterone RIA and VEGF enzyme immunoassay. 3-(4,50-Dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide assay was used to detect the proliferation of Leydig cells. The present results showed that the proliferation of Leydig cells was enhanced significantly by hypoxia. The basal VEGF release was increased, and the response of VEGF production to human chorionic gonadotropin (hCG) was also enhanced in hypoxic condition. During hypoxia, administration of hCG or VEGF stimulated proliferation of Leydig cells, but the stimulatory effect was abolished by the administration of anti-VEGF antibody. Higher doses of VEGF stimulated testosterone release in a dose-dependent manner. Administration of anti-VEGF antibody abolished the stimulatory effect of VEGF on testosterone release. These data suggest that hypoxia stimulates cell proliferation and testosterone release in Leydig cells via an increase of VEGF production.

Caspase-3 and VEGF immunopositivity in seminiferous tubule germ cells in cases of obstructive and non-obstructive azoospermia in smokers versus non-smokers

“…During hypoxia, VEGF promotes angiogenesis in the testis. Hypoxia, in turn, stimulates cell proliferation and testosterone release in Leydig cells via an increase of VEGF production [31]. In our study, we also found an increased VEGF immunoactivity in Leydig cells in the specimens of smokers.…”

NAMPT (visfatin) in the chicken testis: influence of sexual maturation on cellular localization, plasma levels and gene and protein expression

“…VEGF expression has been detected in mouse Sertoli cells, whereas its receptors are located in spermatocytes and spermatids (Nalbandian et al 2003). Hypoxia increases testosterone release in the mouse TM3 cell line mediated by increased VEGFA production (Hwang et al 2007). Interestingly, hypoxia leads to an increase in NAMPT gene expression in adipocytes and in a breast cancer cell line (Bae et al 2006, Segawa et al 2006.…”

Critical role of TRPC6 in maintaining the stability of HIF-1α in glioma cells under hypoxia

“…We next studied the possible ligands released during hypoxia (Ghezzi et al, 1991;Ambalavanan et al, 1999;Michiels et al, 2000;Mouta Carreira et al, 2001;Hwang et al, 2007) that could stimulate GPCRs or RTKs to activate TRPC6 and mediate the hypoxia-induced intracellular Ca 2+ elevation. Treatment of cells with 3-nitrocoumarin, an agent known to inhibit PLCγ activity without affecting PLCβ, but not its inactive analog 7-OH-3-nitrocoumarin, substantially suppressed the Ca 2+ elevation (Fig.…”