NR3C1 and asthma: Mahboub et al. have shown that vitamin D supplementation (50,000 IU) in asthma patients with vitamin D deficiency (less than 20 ng/mL) improves steroid response by increasing the expression of glucocorticoid receptor (GR-α) and reducing blood levels of the asthma related cytokines IL-17F and IL-4 [21].