Effect of TRH on pentagastrin-induced gastric acid secretion.

Thyrotrophin-releasing hormone (TRH) 20 and 30 micrograms . kg-1 i.v. exerted a moderate inhibition on pentagastrin stimulated gastric secretion in dogs provided with gastric fistula and Heidenhain pouch. The effect was more evident in the main stomach than in the denervated pouch. The inhibitory action of the tripeptide was observed, though to a lesser extent, also in gastric fistula cats, whereas it was completely absent in the anaesthetized rat. Our results showing poor and erratic effects of TRH obtained only with rather high intravenous doses, paralleled those obtained by other authors on gastrointestinal motility and support the suggestion that, if there is a physiological role for TRH in the gastrointestinal tract this is more likely connected with paracrine rather than with endocrine effects of the peptide.