Enhanced triiodothyronine production in crested newts bearing permanent lesions to the anterior preoptic area.

In the crested newt, permanent lesions to the anterior preoptic area brought about an enhancement of triiodothyronine (T3) production. This was not mediated by prolactin, since the effect was demonstrable also in ergocryptine (CB 154)-treated animals. The observed rise in circulating T3 levels in the ergocryptine-treated surgical animals confirms that lesions to the anterior preoptic area stimulate pituitary thyrotrophic activity, resulting in the activation of the thyroid gland.