Enclomifene infertility drug, molecular model. The drug clomifene, used to treat infertility in women, is made up of two components, enclomifene (shown here) and zuclomifene. These molecules are geometric isomers, or mirror images of each other. Together, they act on the pituitary gland in the brain, which detects levels of the female sex hormone oestrogen. Fooled into thinking levels of oestrogen are low, the pituitary encourages the release of follicle stimulating hormone (FSH), leading to higher ovulation rates and a greater chance of pregnancy. In this model, atoms are represented by coloured spheres; carbon is light blue, hydrogen is white, oxygen is red, nitrogen is dark blue, and chlorine is green.