Abstract
These experiments were designed to determine whether fasting and feeding were associated with differing rates of protein synthesis in the rat pancreas. It has been established that feeding, acetylcholine, or cholecystokinin-pancreozymin administration was associated with enhanced rates of digestive enzyme secretion; however, the literature is unclear as to effects of such stimulation on enzyme synthesis. Rats fed ad lib. or fasted 24, 48, or 72 hr were used for this study. Pancreases were removed and incubated in tissue culture medium with l-phenylalanine-14C, and incorporation into TCA-insoluble material as well as purified amylase was measured. Compared with fed controls, fasting 24, 48, and 72 hr was associated with 29%, 39%, and 35% decreases in incorporation of l-phenylalanine-14C into protein. Decreases of similar magnitudes were apparent whether the data were expressed in terms of protein or DNA. Pancreatic amylase isolated from rats fasted 48 hr contained 57% fewer counts of l-phenylalanine-14C than amylase isolated from fed rats. Moreover, rats fasted for 24 hr and given bethanechol chloride incorporated greater amounts of l-phenylalanine-14C into protein than fasted controls. Studies were performed to exclude changes in pool size of precursor (l-phenylalanine-14C) or product (amylase) in accounting for decreases associated with fasting. These studies demonstrate that fasting was associated with decreased rates of pancreatic amylase and protein synthesis in rats.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- DICKMAN S. R., HOLTZER R. L., GAZZINELLI G. Protein synthesis by beef pancreas slices. Biochemistry. 1962 Jul;1:574–580. doi: 10.1021/bi00910a006. [DOI] [PubMed] [Google Scholar]
- FERNANDES J. F., JUNQUEIRA L. C. Protein and ribonucleic acid turnover rates related to activity of digestive enzymes of pigeon pancreas. Arch Biochem Biophys. 1955 Mar;55(1):54–62. doi: 10.1016/0003-9861(55)90541-5. [DOI] [PubMed] [Google Scholar]
- HANKING B. M., ROBERTS S. INFLUENCE OF AMINO-ACID LEVELS ON PROTEIN SYNTHESIS IN VITRO. Nature. 1964 Dec 19;204:1194–1195. doi: 10.1038/2041194a0. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Leroy J., Morisset J. A., Webster P. D. Dose-related response of pancreatic synthesis and secretion to cholecystokinin-pancreazymin. J Lab Clin Med. 1971 Jul;78(1):149–157. [PubMed] [Google Scholar]
- Morisset J. A., Webster P. D. In vitro and in vivo effects of pancreozymin, urecholine, and cyclic AMP on rat pancreas. Am J Physiol. 1971 Jan;220(1):202–208. doi: 10.1152/ajplegacy.1971.220.1.202. [DOI] [PubMed] [Google Scholar]
- Poort C., Kramer M. F. Effect of feeding on the protein synthesis in mammalian pancreas. Gastroenterology. 1969 Dec;57(6):689–696. [PubMed] [Google Scholar]
- Redman C. M., Siekevitz P., Palade G. E. Synthesis and transfer of amylase in pigeon pancreatic micromosomes. J Biol Chem. 1966 Mar 10;241(5):1150–1158. [PubMed] [Google Scholar]
- SCHUCHER R., HOKIN L. E. The synthesis and secretion of lipase and ribonuclease by pigeon pancreas slices. J Biol Chem. 1954 Oct;210(2):551–557. [PubMed] [Google Scholar]
- VOLKIN E., COHN W. E. Estimation of nucleic acids. Methods Biochem Anal. 1954;1:287–305. doi: 10.1002/9780470110171.ch11. [DOI] [PubMed] [Google Scholar]
- Webster P. D., 3rd Effect of methacholine on pancreatic amylase synthesis. Gastroenterology. 1968 Sep;55(3):375–385. [PubMed] [Google Scholar]
- Webster P. D., 3rd Effect of stimulation on pancreatic amylase secretion and nuclear RNA synthesis. Proc Soc Exp Biol Med. 1969 Dec;132(3):1072–1076. doi: 10.3181/00379727-132-34369. [DOI] [PubMed] [Google Scholar]
- Webster P. D., Tyor M. P. Effect of fasting and feeding on lipid metabolism of pigeon pancreas. Am J Physiol. 1966 May;210(5):1076–1079. doi: 10.1152/ajplegacy.1966.210.5.1076. [DOI] [PubMed] [Google Scholar]
- Webster P. D., Tyor M. P. Effect of intravenous pancreozymin on amino acid incorporation in vitro by pancreatic tissue. Am J Physiol. 1966 Jul;211(1):157–160. doi: 10.1152/ajplegacy.1966.211.1.157. [DOI] [PubMed] [Google Scholar]
- Webster P. D., Tyor M. P. Effect of intravenous pancreozymin on amino acid incorporation in vitro by pancreatic tissue. Am J Physiol. 1966 Jul;211(1):157–160. doi: 10.1152/ajplegacy.1966.211.1.157. [DOI] [PubMed] [Google Scholar]
- Webster P. D., Tyor M. P. Effects of fasting and feeding on uridine-3-H incorporation into RNA by pancreas slices. Am J Physiol. 1967 Jan;212(1):203–206. doi: 10.1152/ajplegacy.1967.212.1.203. [DOI] [PubMed] [Google Scholar]