DISTRIBUTION OF SOLUBLE PROTEINS IN THE MAMMALIAN NEUROHYPOPHYSIS AND THEIR CROSS-SPECIES REACTIVITY WITH ANTI-NEUROPHYSIN

Abstract

SUMMARY Pituitary glands were collected from a selection of 22 domestic and exotic mammalian species. The soluble proteins extracted from the neurohypophyses were characterized by horizontal starch-gel electrophoresis at pH 8·1. Those species which were closely related phylogenetically, e.g. fallow deer and muntjac deer, pig and hippopotamus, dog and coatimundi, and members of the primates, had similar and in some cases identical protein profiles. The ability of proteins extracted from the starch-gel to cross-react immunologically with an antiserum raised against porcine neurophysin-II was determined by microimmunodiffusion. Using this technique for the identification of neurophysins in conjunction with osmotic stimulation experiments, it was found that the number of major neurophysins present in the mammalian neurohypophyses studied varied from one in the guinea-pig and hedgehog to four in man. The concept of multiple neurophysins is discussed.