ISSN:
0002-9106
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The cytological basis for protein transport across the guinea pig visceral yolk sac at 36-44 days of gestation was studied by means of electron microscopy following injection of horseradish peroxidase and ferritin. These results were compared with those obtained after administration of colloidal thorium dioxide. Distribution of the tracer molecules was studied at 2, 10, 20, 40, and 160 minutes after injection into the uterine lumen. All three tracer molecules were rapidly absorbed by endoderm cells. Although most of the protein appeared to be retained in droplets in endoderm cells, some protein was transmitted. Peroxidase was found to be rapidly transmitted across the yolk sac, ferritin somewhat more slowly, and colloidal thorium was not transmitted at all. Protein which had exited from the endoderm cells followed any of three pathways: (1) it crossed the visceral basement membrane and entered the vitelline capillaries; (2) it crossed the mesodermal compartment, crossed the mesothelial cells and entered the exocoelomic cavity; or (3) some of the protein was sequestered by macrophages in the splanchnic mesoderm. The pathways observed are consistent with those suggested by previous authors for the passage of maternal antibodies and serum proteins to the guinea pig fetus.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aja.1001290303
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