PF-04859989 HCl is a brain-penetrable and irreversible inhibitor of kynurenine amino transferase II (KAT II), which is the enzyme responsible for most of the brain synthesis of kynurenic acid.

CDR-H3/C2

Histrelin acetate is a nonapeptide analog of gonadotropin-releasing hormone (GnRH) with added potency. It acts on particular cells of the pituitary gland called gonadotropes when present in the bloodstream. Histrelin stimulates these cells to release luteinizing hormone and follicle-stimulating hormone. Thus it is considered a gonadotropin-releasing hormone agonist or GnRH agonist.