Effect of a high-protein diet on the gene expression of a trypsin-sensitive, cholecystokinin-releasing peptide (monitor peptide) in the pancreas.
The adaptation to a high protein diet of the concentration and mRNA level of a trypsin-sensitive, cholecystokinin-releasing peptide (monitor peptide), which was proposed to be the mediator of the cholecystokinin release in response to protein intake, was investigated in the rat pancreas. Adult rats were placed on one of two isocaloric diets. One group was fed a 22% casein diet (control diet) and the other a 64% casein diet (high-protein diet) for 14 days. In order to quantify the monitor peptide separately from pancreatic secretory trypsin inhibitor (PSTI-II), which is highly similar in its amino acid and mRNA nucleotide sequences to the monitor peptide but has less cholecystokinin-releasing activity, we used specific assay methods: HPLC was used for determining the monitor peptide concentration in zymogen granules and a synthetic oligonucleotide probe for determining the mRNA of the monitor peptide in the pancreas. The concentrations in the zymogen granules and the mRNA levels in the pancreas of the two peptides increased in parallel during the adaptation to the high protein diet, indicating that these two peptides were under the same control during the adaptation. The concentration and mRNA level of the monitor peptide, which were measured after 0, 3, and 14 days, increased throughout the experiment period, as did the concentration of trypsin. This suggested that the monitor peptide and trypsin may respond to similar signals during the adaptation to a high protein diet and that this apparent coordination may facilitate the adaptation of the pancreas to the diet.
Tsuzuki
S
S
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Fushiki
T
T
Kondo
A
A
Murayama
H
H
Sugimoto
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001835:Body Weight; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000302:isolation & purification; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D004792:Enzyme Precursors / Q000378:metabolism; D005247:Feeding Behavior; D005786:Gene Expression Regulation; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009929:Organ Size; D010179:Pancreas / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine; D014357:Trypsin / Q000378:metabolism*; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000235:genetics* / Q000378:metabolism
D004044:Dietary Proteins; D004792:Enzyme Precursors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; C504705:Spink1 protein, rat; D014359:Trypsin Inhibitor, Kazal Pancreatic; D004247:DNA; D014357:Trypsin