Pseurotin A is a secondary metabolite produced by Aspergillus and other fungi. Its expression is induced in response to hypoxia. Pseurotin A is a secondary metabolite produced by Aspergillus and other fungi. Its expression is induced in response to hypoxia. Pseurotin A has been shown to inhibit IgE production by mouse B cells in culture (IC50 = 3.6 μM) and dose-dependently (0.4-25 μg/ml) stimulate neuritogenic activity in rat pheochromocytoma PC12 cells. It also demonstrates nematicidal activity at 300 μg/ml.