Additionally, administration of MT may improve oocyte development by increasing the expression of oocyte maturation-related genes, namely, growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) (78); it also reverses the low progesterone levels observed in PCOS by upregulating StAR expression in GCs (79). This evidence concerns the gene GDF9 and polycystic ovary syndrome.