Summary
Secretory granule extrusion in cells of the rat anterior pituitary was studied by electron microscopy. After appropriate stimulation, corticotrophs, somatotrophs and thyrotrophs showed both “in vivo” and “in vitro” (tissue culture) the extrusion of granules by reverse pinocytosis (exocytosis). In contrast, this phenomenon is not observed in gonadotrophs.
Granule extrusion takes place only at those parts of the cell which are in contact with the basement membrane. This directed release seems to favor a quicker diffusion of hormones to the circulatory system.
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The study was supported by C.N.R.S. (E.R.A. 42) and the Medical Research Council of Canada. The authors wish to thank Dr. F. Girard who did the ACTH and corticosterone determinations, Dr. A. B. Novikoff for critical reading of the manuscript, and Miss A. Devaux for her technical assistance. They are particularly indebted to Professor J. Racadot and his colleagues for their many helpful discussions during the performance of this work.
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Pelletier, G., Peillon, F. & Vila-Porcile, E. An ultrastructural study of sites of granule extrusion in the anterior pituitary of the rat. Z. Zellforsch. 115, 501–507 (1971). https://doi.org/10.1007/BF00335716
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DOI: https://doi.org/10.1007/BF00335716