Motilin stimulates growth hormone release in vitro

Motilin, a twenty two amino acid polypeptide originally isolated from duodenal extracts, has been detected recently in the mammalian hypothalamus and pituitary. We have investigated the possibility that motilin might play a role in neuroendocrine events and report here the ability of synthetic porcine motilin (10(-6)M) to stimulate growth hormone release from rat hemipituitaries and dispersed anterior pituitary cells in vitro. No significant effects on luteinizing hormone, thyroid stimulating hormone or prolactin release were observed. Motilin may be added therefore to the growing list of gastrointestinal hormones which can act directly at the level of the anterior pituitary to alter hormone release.