INHA and ovarian cancer: Supporting our hypothesis that inhibin is regulated by hypoxia, we also found that exposure of ovarian cancer cells to hypoxia increased INHA expression and inhibin secretion most significantly at 0.2% oxygen after 24 h (Fig. 1) While a trend towards increase in INHA was seen at higher oxygen tensions (2.5% and 1%), these did not reach significance and could be due to additional time or additional factors needed at higher oxygen levels.