In the endocrine system, honokiol activates the ERK/c-fos signaling pathway, increases GDNF levels [83], increases the mRNA expression of glucocorticoid receptors in the hippocampus [84], improves insulin resistance in type 2 diabetic db/db mice [85], and inhibits 5-alpha-reductase type 1, modulating testosterone levels in vitro [82]. Here, GDNF is linked to Insulin resistance.