Microheterogeneous neurophysins in newly formed and aged neurosecretory granules

To find out, whether microheterogeneity of neurophysins is due to aging of neurosecretory granules we investigated neurophysin proteins of porcine origin from newly formed and aged granules, as well as from two different extraction methods from whole posterior pituitary glands by high performance liquid chromatography. In newly formed as well as in aged granules all microheterogeneous forms of the neurophysins were present in nearly identical relation suggesting that microheterogeneity is not due to maturation or post matural degradation. In comparison, the crude material obtained by the method of Uttenthal and Hope showed a comparable content of the different neurophysins while Chauvet's method resulted in a different HPLC pattern. In summary, neurophysin heterogeneity is obviously not due to aging processes.