Summary
Subcellular structures of pancreatic acinar cells were examined at six evenly spaced time points in the 24-h period (light cycle: 06.00 h–18.00 h) in four Wistar male rats at each time point. At each sampling point, the area and circumference of acinar cell bodies and the area, number and circumference of their cytoplasmic organelles were measured using a semiautomatic computer system for morphometry and a point-counting method.
The area, number and circumference-area ratio of the cytoplasmic organelles were subject to strong circadian variations, and the cellular area and circumference exhibited weak circadian variations. Variation pattern of the cytoplasmic organelles suggested an intracellular route for secretory proteins during a 24-h span. From the results it was possible to divide the 24-h period into three stages. 1. The resting or protein synthetic stage (00.00 h to 08.00h): the area of the rough surfaced endoplasmic reticulum (rER) was strongly increased, and that of zymogen granules was clearly decreased. 2. The granule accumulation stage (08.00h to 16.00h): the area of the rER was markedly decreased; that of zymogen granules was increased. 3. The secretion stage (16.00 h to 00.00): as a result of the release of zymogen granules from the acinar cell, the area of zymogen granules decreased, and that of the rER increased. The relationship between the area of the rER and zymogen granules varied in a reciprocal manner. Other cytoplasmic organelles, namely the Golgi complex, condensing vacuoles, mitochondria and lysosomes also varied prominently during the 24-h span, corresponding to variations in the rER and zymogen granules.
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References
Adler G (1977) Effect of glucagon on the secretory process in the rat exocrine pancreas. Cell Tissue Res 182:193–204
Albegger KW, Müller O, Albegger Chr (1975) Zur Circadianstruktur der Glandula parotis. Morphologische und morphometrische Untersuchungen. HNO 23:233–236
Bieger W, Seybold J, Kern HF (1976) Studies on intracellular transport of secretory proteins in the rat exocrine pancreas. V. Kinetic studies on accelerated transport following caerulein infusion in vivo. Cell Tissue Res 170:203–219
Bolender RP (1974) Stereological analysis of the guinea pig pancreas. I. Analytical model and quantitative description of nonstimulated pancreatic exocrine cells. J Cell Biol 61:269–287
Cope GH, Williams MA (1973) Quantitative analyses of the constituent membranes of parotid acinar cells and the changes evident after induced exocytosis. Z Zellforsch 145:311–330
Geuze JJ, Slot JW, Tokuyasu DT (1979) Immunocytochemical localization of amylase and chymotrypsinogen in the exocrine pancreatic cell with special attention to the Golgi complex. J Cell Biol 82:697–707
Jamieson JD, Palade GE (1967a) Intracellular transport of secretory proteins in the pancreatic exocrine cell. I. Role of the peripheral elements of the Golgi complex. J Cell Biol 34:577–596
Jamieson JD, Palade GE (1967b) Intracellular transport of secretory proteins in the pancreatic exocrine cell. II. Transport to condensing vacuoles and zymogen granules. J Cell Biol 34:597–615
Jamieson JD, Palade GE (1971) Synthesis, intracellular transport, and discharge of secretory proteins in stimulated pancreatic exocrine cells. J Cell Biol 50:135–158
Johnson DA, Sreebny LM (1973) Effect of isoproterenol on synthesis and secretion in the rat parotid gland. Lab Invest 28:263–269
Meldolesi J (1974) Dynamics of cytoplasmic membranes in guinea pig pancreatic acinar cells. I. Synthesis and turnover of membrane proteins. J Cell Biol 61:1–13
Meldolesi J, Cova D (1972) Composition of cellular membranes in the pancreas of the guinea pig. IV. Polyacrylamide gel electrophoresis and amino acid composition of membrane proteins. J Cell Biol 55:1–18
Meldolesi J, Jamieson JD, Palade GE (1971a) Composition of cellular membranes in the pancreas of the guinea pig. I. Isolation of membrane fractions. J Cell Biol 49:109–129
Meldolesi J, Jamieson JD, Palade GE (1971b) Composition of cellular membranes in the pancreas of the guinea pig. III. Enzymatic activities. J Cell Biol 49:150–158
Palade GE (1975) Intracellular aspects of the process of protein synthesis. Science 189:347–358
Poort C, Kramer MF (1969) Effect of feeding on the protein synthesis in mammalian pancreas. Gastroenterology 57:689–696
Schellens JPM, Daems WTh, Emeis JJ, Brederoo P, Bruijin WC (1977) Electron microscopical identification of lysosomes. In: Dingle JT (ed) Lysosomes. A laboratory handbook. North-Holland Company, Amsterdam-New York-Oxford, pp 147–208
Slot JW, Geuze JJ (1979a) A morphometrical study on the exocrine pancreatic cell in fasted and fed frogs. J Cell Biol 80:692–707
Slot JW, Geuze JJ (1979b) Effect of fasting and feeding on synthesis and intracellular transport of proteins in the frog exocrine pancreas. J Cell Biol 80:708–714
Sreebny LM, Johnson DA (1969) Diurnal variation in secretory components of the rat parotid gland. Arch Oral Biol 14:397–405
Weibel ER (1979) Stereological methods. Practical methods for biological morphometry. Academic Press, London-New York-Toronto-Sydney-San Francisco
Yamashina S, Kawai K (1981) Localization of 5′-nucleotidase activity in the parotid acinar cells of a rat treated with isoproterenol. Cell Tissue Res 214:483–490
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Uchiyama, Y., Saito, K. A morphometric study of 24-hour variations in subcellular structures of the rat pancreatic acinar cell. Cell Tissue Res. 226, 609–620 (1982). https://doi.org/10.1007/BF00214788
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DOI: https://doi.org/10.1007/BF00214788