Effect of beta-casomorphins on somatostatin release in dogs

Endocrinology. 1983 Jun;112(6):1948-51. doi: 10.1210/endo-112-6-1948.


In the present study, the effects of orally administered beta-casomorphins (beta-CM) and met-enkephalin on postprandial plasma somatostatin-like immunoreactivity (SLI) were assessed in conscious dogs. The intragastric instillation of a liver extract-sucrose test meal containing 12 mg beta-CM or 10 mg met-enkephalin, respectively, augmented the postprandial rise of peripheral vein plasma SLI levels significantly. This effect was inhibited by the additional administration of the specific opiate-receptor antagonist, naloxone. When liver extract-sucrose was dissolved in fresh bovine milk the increase of plasma SLI levels was significantly greater than liver extract-sucrose dissolved in water. This milk-induced augmentation of SLI levels was also reduced by naloxone. Since these opiate-active compounds have an influence upon insulin release when given iv, the effect of beta-CM-7, beta-CM-5, beta-CM-4 beta-CM-4-amide, and met-enkephalin on SLI levels was assessed during their iv infusion at a rate of 1 nmol/kg . h during an iv background infusion of a glucose-amino acid mixture. The infusion of beta-CM-5 elicited a stimulation of peripheral vein SLI levels, whereas the infusion of met-enkephalin resulted in a significant decrease of SLI levels. beta-CM-7, beta-CM-4, and beta-CM-4-amide had no effect on plasma SLI levels at the dose employed. The present data demonstrate that in dogs the ingestion of opiate-active peptide stimulates postprandial SLI release, indicating that nutrient-contained opiate-active material (exorphins) might participate in the regulation of postprandial gastrointestinal endocrine function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism
  • Animals
  • Caseins / pharmacology*
  • Dogs
  • Eating
  • Endorphins / pharmacology*
  • Enkephalin, Methionine / pharmacology
  • Kinetics
  • Naloxone / pharmacology
  • Somatostatin / metabolism*


  • Amino Acids
  • Caseins
  • Endorphins
  • Naloxone
  • Somatostatin
  • Enkephalin, Methionine
  • beta-casomorphins