Hypothalamic biosynthesis and transport of neurophysins and their precursors to the rat brain stem.
Twenty-four hours after the injection of [35S]cysteine near either the rat paraventricular nuclei or the supraoptic nuclei, the [35S]neurophysin-like proteins of the brain stem were extracted, immunoprecipitated with anti-bovine neurophysins antibodies and analyzed. They consisted essentially of species behaving as neurophysin on sodium dodecyl sulfate--polyacrylamide gel electrophoresis. There was a very low percentage of neurophysins precursors which could be characterized in the paraventricular nuclei. In the rats pretreated by colchicine, the [35S]neurophysins were not detected in the brain stem, while they appeared in the paraventricular nuclei indicating that the precursors have been processed and the transport inhibited. These results suggest that: (i) both the biosynthetic and transport events in the hypothalamo-brain stem pathway are comparable to those occurring in the hypothalamo-neurohypophyseal tract; (ii) this pathway originates both from the supraoptic and paraventricular nuclei. Moreover, they indicate that processing is essentially complete in the hypothalamus of colchicine-pretreated animals. This provides further support to a model associating enzymes with both the endoplasmic reticulum membranes and the derived corresponding secretory vesicles.
D000818:Animals; D001931:Brain Mapping; D001933:Brain Stem / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007031:Hypothalamus / Q000378:metabolism*; D008125:Locus Coeruleus / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000378:metabolism; D009481:Neurophysins / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000378:metabolism
D009481:Neurophysins; D014667:Vasopressins; D010121:Oxytocin