A model for the passage of the nurohypophysial hormones and their related proteins through the rat neurohypophysis.
The change in the radioactivity of vasopressin-neurophysin in the rat neurohypophysis after an intracisternal injection of [(35)S]cysteine was fitted to several mathematical models. The data fitted best a model in which there is a linear input of radioactive protein into one pool of the neurohypophysis, from which it is either released by an exponential process or transferred to a second pool from which it is released by a second exponential process with a rate constant much lower than the first. This model is compatible with the existence of a ;readily releasable' pool first postulated by Sachs et al. (1967). Data for the change in radioactivity of vasopressin also gave a good fit in this model. Calculation of the rate constants suggested that the first pool represented about 2% of the total hormone.
D000818:Animals; D003201:Computers; D003545:Cysteine / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D008433:Mathematics; D008954:Models, Biological; D009481:Neurophysins / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D013462:Sulfur Radioisotopes; D014667:Vasopressins / Q000378:metabolism*
D009481:Neurophysins; D011506:Proteins; D013462:Sulfur Radioisotopes; D014667:Vasopressins; D003545:Cysteine