But T three and T four, as this builds up in its concentration it creates a negative feedback loop in terms of the interior pituitary and the hypothalamus. So the build up in this causes our interior pituitary and the hypothalamus to stop producing our TRH and the TSH. Now, the next hormone that is produced by the interior pituitary gland is our prolactin. So prolactin is basically stimulated or actually it's not stimulated. So the interesting thing about prolactin is the hormone that is produced by the hypothalamus known as the prolactin inhibitory hormone actually inhibits the release of prolactin. And this is the only hormone that basically does this.