TRH-like immunoreactivity in endocrine cells and neurons in the gastro-intestinal tract of the rat and guinea pig.
By use of the indirect immunofluorescence technique, the cellular localization of thyrotropin-releasing hormone (TRH) was studied in the gastrointestinal tract of rats and guinea pigs of different ages. TRH-like immunoreactivity (LI) was observed in many pancreatic islet cells of young rats and guinea pigs but only in single cells of 6-month-old rats. In aged guinea pigs, a reduction in the number of TRH-positive cells was evident; however, numerous strongly fluorescent cells were still present. In the guinea pig, TRH-LI was in addition observed in gastrin cells in the stomach. TRH-positive nerve fibers occurred in the myenteric plexus of the oesophagus, stomach and intestine of the rat, and in the muscle layers of the guinea pig. These results suggest a functional role of TRH both as hormone and neuroactive compound in various portions and sites of the gastro-intestinal tract of the rat and guinea pig.
D000818:Animals; D004064:Digestive System / Q000032:analysis* / Q000294:innervation; D004702:Endocrine Glands / Q000032:analysis*; D006168:Guinea Pigs; D007150:Immunohistochemistry; D007515:Islets of Langerhans / Q000032:analysis* / Q000378:metabolism; D008297:Male; D051381:Rats; D013270:Stomach / Q000032:analysis* / Q000294:innervation; D013973:Thyrotropin-Releasing Hormone / Q000032:analysis*
D013973:Thyrotropin-Releasing Hormone