Investigation of the effects of enteral hormones on the pyloric muscle in newborn rats

J Pediatr Surg. 2015 Mar;50(3):408-12. doi: 10.1016/j.jpedsurg.2014.05.036. Epub 2014 Jul 4.


Purpose: To investigate the effects of enteral hormones on pyloric muscle in order to clarify the etiopathogenesis of hypertrophic pyloric stenosis (HPS).

Methods: Forty-two newborn Wistar-Albino rats were included. No intervention was done in the control group (CG, n=6). In the sham group (SG, n=6) 1ml saline (0.9% NaCl solution), in the Nw-nitro-l-arginine methyl ester hydrochloride (L-NAME) group (LNG, n=6) 100mg/kg/d L-NAME, in the somatostatin group (STG, n=6) 7mcg/kg/d ST, in the cholecystokinin group (CCKG, n=6) 3mcg/kg/d CCK, in the substance P group (SPG, n=6) 5ml/kg/d SP, and in the prostaglandin-E1 group (PGE1G, n=6) a cumulative dose of 360mcg/kg PGE1 was given intraperitoneally for 14days. On the 21st day, histopathological examination and muscle thickness measurements were done. Results were evaluated statistically.

Results: Total and circular pyloric muscle thicknesses were significantly increased in the LNG compared to the CG and SG (p<0.05). Circular pyloric muscle thickness was not increased in the STG, CCKG and SPG compared to the CG and SG (p>0.05). In the PGE1G, muscle thickness was significantly decreased in the pylorus and increased in the antrum compared to the CG and SG (p<0.05).

Conclusion: Nitric oxide synthase (NOS) inhibition with L-NAME seems to be a causative factor in HPS by increasing pyloric muscle thickness. PGE predominantly affects antral gastric muscle and has no profound effect on pyloric muscle.

Keywords: Enteral hormones; Hypertrophic pyloric stenosis; L-NAME; Prostaglandin; Pyloric muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn*
  • Arginine / analogs & derivatives*
  • Arginine / pharmacology
  • Disease Models, Animal
  • Enzyme Inhibitors / pharmacology
  • Female
  • Male
  • NG-Nitroarginine Methyl Ester / pharmacology*
  • Pyloric Stenosis, Hypertrophic / etiology*
  • Pyloric Stenosis, Hypertrophic / pathology
  • Pylorus / drug effects*
  • Pylorus / pathology
  • Rats
  • Rats, Wistar


  • Enzyme Inhibitors
  • arginine methyl ester
  • Arginine
  • NG-Nitroarginine Methyl Ester