Circadian and Ultradian Variation in Pancreatic Secretion of Meal-Fed Pigs after Weaning

M. J. Thaela, M. S. Jensen, Germaine G Cornelissen-Guillaume, F. Halberg, F. Nöddegaard, K. Jakobsen, S. G. Pierzynowski

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21 Scopus citations


We studied the time structure of pancreatic secretion in two experiments involving seven 6- to 7-wk-old intact male pigs, surgically fitted with a jugular vein catheter for blood sampling, pancreatic catheter, and a duodenal T-cannula for chronic pancreatic juice sampling for 72 h at 30- to 60-min intervals. Pigs were kept in metabolic cages in a regimen of 12 h of light alternating with 12 h of darkness and were fed at 0800, 1500, and 2200 daily a standard diet based on barley, soybean meal, and fish meal. Beginning 4 d after surgical recovery three 24-h collections of pancreatic juice and blood sampling were begun either at 0700 or 0800 every 2nd d for 5 d. Pancreatic secretion exhibited a pattern characterized by distinct meal-related secretions of the first phase (postprandial), containing large amounts of protein and enzymes (trypsin and chymotrypsm), and by non-food-stimulated secretions of the second phase with less protein and enzymes. During the dark span, the first phase was practically absent; the response of the pancreatic secretion to the 2200 meal was not very pronounced. Apart from the anticipated circadian rhythm demonstrable by single cosinor analysis on a group basis, a prominent 8-h component was almost invariably statistically significant. Moreover, an approximately 3.43-h component was also prominent. These data indicate that pancreatic secretions are circadian periodic and that their response to a standard meal is also circadian-stage dependent. The circadian components may have been free-running because the pigs were adjusting themselves to the changing phase and that resulted in the period being different from exactly 24 h.

Original languageEnglish (US)
Pages (from-to)1131-1139
Number of pages9
JournalJournal of animal science
Issue number4
StatePublished - Apr 1998


  • Circadian Rhythm
  • Pancreas
  • Pigs
  • Protein
  • Trypsin


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