During secretion of the neurohypophysial hormones, oxytocin and vasopressin, secretory granule membrane is added to the plasma membrane of the axon terminals. It is generally assumed that subsequent internalization of this additional membrane occurs by endocytosis. In order to study this process, we have traced the uptake of intravenously injected horseradish peroxidase by neurohypophysial axons in rats and golden hamsters. Peroxidase reaction product within the secretory axons was found mainly in vacuolar and C-shaped structures of a size comparable with or larger than the neurosecretory granules. Our observations suggest that these large horseradish peroxidase (HRP)-impregnated vacuoles arise directly by a form of macropinocytosis. Morphometric analysis indicated that this form of membrane retrieval increased significantly after the two types of stimuli used, reversible hemorrhage and electrical stimulation of the pituitary stalk. Microvesicular uptake of HRP was found to be comparatively less.
Article| August 01 1976
Secretion-related uptake of horseradish peroxidase in neurohypophysial axons.
D T Theodosis,
D T Theodosis
M C Harris
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1976) 70 (2): 294–303.
D T Theodosis, J Dreifuss, M C Harris, L Orci; Secretion-related uptake of horseradish peroxidase in neurohypophysial axons.. J Cell Biol 1 August 1976; 70 (2): 294–303. doi: https://doi.org/10.1083/jcb.70.2.294
Download citation file: