Endocytosis of surface bound dopamine β-hydroxylase and plasma membrane following catecholamine secretion by bovine adrenal chromaffin cells

Lotshaw, David P.; Ye, H.Z.; Edwards, Charles

doi:10.1016/0197-0186(86)90081-1

Cited by 6 publications

(1 citation statement)

References 17 publications

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“…A reverse process, membrane internalization, has been demonstrated in a number of cell types by using extracellular markers, such as dextran, horseradish peroxidase and ferritins (see Herzog & Farquhar, 1977;Farquhar, 1982Farquhar, , 1985Oliver et aI., 1989). Several lines of evidence suggest that the membrane of the exocytosed secretory granule is specifically re-internalized, not merely random areas of plasma membrane (de Camilli et al, 1976;Theodosis, 1983;Lotshaw et al, 1986;Patzak & Winkler, 1986). Two major pathways have been described for the internalized membrane material; degradation in lysosomes or eventual re-utilization for granule formation in the Golgi complex (see Oliver & Hand, 1978;Farquhar, 1978Farquhar, , 1982Farquhar, , 1985Herzog & Miller, 1979;Thyberg, 1980;Rosenzweig & Kanwar, 1984).…”

Section: Introductionmentioning

confidence: 99%

Endocytotic pathways in the melanotroph of the rat pituitary

1993

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The internalization of the extracellular markers horseradish peroxidase (HRP) and cationized ferritin (CF) by the melanotrophs of the intermediate lobe of the rat pituitary was studied during short-time incubation of mechanically dissociated cells or in cell culture after 5 days. After a 30 min exposure, the tracers were found in electron-lucent granules or vacuoles of approximately the same size as the secretory granules, situated 200-500 nm from the cell membrane. In the cultured cells, which showed a higher rate of tracer uptake, internalization was followed for 1, 2 and 5 min after labelling and during 2 h of exposure. Initially, the label was seen only in coated pits and coated vesicles at the cell membrane. Larger vacuoles were first seen after 2-5 min of incubation. After 2 h of exposure the labelling pattern was distinctly different for the two tracers. CF was found in larger vacuoles of varying morphology, in dilatations at the base of cilia, within Golgi saccules and at the edge of the electron-dense core of forming secretory granules. HRP was found in an extensive array of tubulovesicular structures extending throughout the cytoplasm. The Golgi complex and forming granules were, however, not labelled with HRP. The study identifies part of the electron-lucent granules or vacuoles in the melanotroph as endosomes, and shows that the melanotrophs sort CF and HRP via diverting pathways after internalization, suggesting that granule membrane, and possibly its functional components, can be recycled in these cells.

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