Multiple-rate components of axonally transported proteins in the hypothalamo-neurohypophysial system of the rat.

The transport of labeled proteins from the hypothalamus to the neurohypophysis following 35S-methionine injection into the rat supraoptic nucleus was studied using a unique approach adapted for the study of short-axon systems. Multiple-rate components to those found in other neuronal systems were demonstrated. Neurosecretory vesicle-containing proteins (e.g., neurophysins) were transported at fast rates (greater than 120 mm/day), whereas the cytoskeletal protein, actin, moved principally in the slow component of transport. Two-dimensional gel electrophoresis was used to analyze the diverse patterns of labeled proteins found in the various rate components of axonal transport in this system.