Skip to main content
NCBI home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1962 Nov 1;15(2):259–277. doi: 10.1083/jcb.15.2.259

THE IDENTIFICATION OF CHYLOMICRA AND LIPOPROTEINS IN TISSUE SECTIONS AND THEIR PASSAGE INTO JEJUNAL LACTEALS

J R Casley-Smith 1
PMCID: PMC2106149  PMID: 14019085

Abstract

The electron microscopic appearances of chylomicra and lipoproteins have been investigated. The particles were isolated from rat chyle by differential flotation in an ultracentrifuge. Various fixing and embedding media were used. The two kinds of particles were then identified in thin sections of the jejunum of rats. The chylomicra had diameters of from 1,000 A to 1 µ; the lipoproteins ranged from 100 to 1,000 A. They were identified by their sizes and their similarities to the isolated particles after the various fixing and embedding procedures. In addition, the relative amounts of the two kinds of particle varied greatly under different dietary conditions. The chylomicra had a thin rim, probably of phospholipid. Section B records the passage of the two kinds of particle into the lacteals in the villi of the jejunum. Both chylomicra and lipoproteins were seen passing through many open junctions. From permeability considerations it would seem that this is the most important route. These open junctions appear to act as "inlet valves" which prevent backflow as the contractions of the villi pump material out of the lacteals. Both chylomicra and lipoproteins were also seen entering the endothelial cells and lying inside them. The lipoproteins entered via "normal" caveolae and were seen in "normal" vesicles (∼500 A); the chylomicra necessarily occupied much larger organelles. Both kinds of particles were also seen in caveolae on the luminal surface of the endothelium, but it was impossible to be certain that these were not just particles entering the cells from the lumen. The chylomicra often seemed to be washed out of these caveolae as many large, empty ones were seen on the luminal sides of the cells. Frequently, these caveolae had dark membranes.

Full Text

The Full Text of this article is available as a PDF (2.1 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ASHWORTH C. T., STEMBRIDGE V. A., SANDERS E. Lipid absorption, transport and hepatic assimilation with electron microscopy. Am J Physiol. 1960 Jun;198:1326–1328. doi: 10.1152/ajplegacy.1960.198.6.1326. [DOI] [PubMed] [Google Scholar]
  2. BRAGDON J. H. On the composition of chyle chylomicrons. J Lab Clin Med. 1958 Oct;52(4):564–570. [PubMed] [Google Scholar]
  3. CASLEY-SMITH J. R., FLOREY H. W. The structure of normal small lymphatics. Q J Exp Physiol Cogn Med Sci. 1961 Jan;46:101–106. doi: 10.1113/expphysiol.1961.sp001502. [DOI] [PubMed] [Google Scholar]
  4. CAULFIELD J. B. Effects of varying the vehicle for OsO4 in tissue fixation. J Biophys Biochem Cytol. 1957 Sep 25;3(5):827–830. doi: 10.1083/jcb.3.5.827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. CLARK S. L., Jr The ingestion of proteins and colloidal materials by columnar absorptive cells of the small intestine in suckling rats and mice. J Biophys Biochem Cytol. 1959 Jan 25;5(1):41–50. doi: 10.1083/jcb.5.1.41. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. FILLERUP D. L., MIGLIORE J. C., MEAD J. F. The uptake of lipoproteins by ascites tumor cells: the fatty acid-albumin complex. J Biol Chem. 1958 Jul;233(1):98–101. [PubMed] [Google Scholar]
  7. FRENCH J. E., FLOREY H. W., MORRIS B. The absorption of particles by the lymphatics of the diaphragm. Q J Exp Physiol Cogn Med Sci. 1960 Jan;45:88–103. doi: 10.1113/expphysiol.1960.sp001448. [DOI] [PubMed] [Google Scholar]
  8. GORDON G. B., KING D. W. Phagocytosis. Am J Pathol. 1960 Sep;37:279–292. [PMC free article] [PubMed] [Google Scholar]
  9. HAMPTON J. C. An electron microscope study of the hepatic uptake and excretion of submicroscopic particles injected into the blood stream and into the bile duct. Acta Anat (Basel) 1958;32(3):262–291. doi: 10.1159/000141328. [DOI] [PubMed] [Google Scholar]
  10. HAYES T. L., HEWITT J. E. Visualization of individual lipoprotein macromolecules in the electron microscope. J Appl Physiol. 1957 Nov;11(3):425–428. doi: 10.1152/jappl.1957.11.3.425. [DOI] [PubMed] [Google Scholar]
  11. LUFT J. H. Improvements in epoxy resin embedding methods. J Biophys Biochem Cytol. 1961 Feb;9:409–414. doi: 10.1083/jcb.9.2.409. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. MAJNO G., PALADE G. E. Studies on inflammation. 1. The effect of histamine and serotonin on vascular permeability: an electron microscopic study. J Biophys Biochem Cytol. 1961 Dec;11:571–605. doi: 10.1083/jcb.11.3.571. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. MOORE D. H., RUSKA H. The fine structure of capillaries and small arteries. J Biophys Biochem Cytol. 1957 May 25;3(3):457–462. doi: 10.1083/jcb.3.3.457. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. McMASTER P. D., PARSONS R. J. The movement of substances and the state of the fluid in the intradermal tissue. Ann N Y Acad Sci. 1950 May 31;52(7):992–1003. doi: 10.1111/j.1749-6632.1950.tb53995.x. [DOI] [PubMed] [Google Scholar]
  15. PALAY S. L., KARLIN L. J. An electron microscopic study of the intestinal villus. I. The fasting animal. J Biophys Biochem Cytol. 1959 May 25;5(3):363–372. doi: 10.1083/jcb.5.3.363. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. PALAY S. L., KARLIN L. J. An electron microscopic study of the intestinal villus. II. The pathway of fat absorption. J Biophys Biochem Cytol. 1959 May 25;5(3):373–384. doi: 10.1083/jcb.5.3.373. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. ROBINSON D. S., FRENCH J. E. Heparin, the clearing factor lipase, and fat transport. Pharmacol Rev. 1960 Jun;12:241–263. [PubMed] [Google Scholar]
  18. ROBINSON D. S. The chemical composition of chylomicra in the rat. Q J Exp Physiol Cogn Med Sci. 1955 Apr;40(2):112–126. doi: 10.1113/expphysiol.1955.sp001103. [DOI] [PubMed] [Google Scholar]
  19. THOMAS W. A., O'NEAL R. M. Electron microscopy studies of butter and corn oil in jejunal mucosa. Arch Pathol. 1960 Feb;69:121–129. [PubMed] [Google Scholar]
  20. WATSON M. L. Staining of tissue sections for electron microscopy with heavy metals. J Biophys Biochem Cytol. 1958 Jul 25;4(4):475–478. doi: 10.1083/jcb.4.4.475. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES