Байгалийн HGH эсвэл өсөлтийн даавар өнчин тархины булчирхайн үйлдвэрлэж байна; a very tiny gland located deep at the base of the brain. The pituitary is about the size of a pea but it's extremely powerful, nicknamed the "мастер булчирхайн" байгууллага.