Regional distribution of chromogranin B 420–493-like immunoreactivity in the pituitary gland and central nervous system of man, guinea-pig and rat

Abstract

The distribution of chromogranin B 420–493-like immunoreactivity was investigated in the pituitary gland and central nervous system of man, guinea-pig and rat, by using two different antibodies. In man, highest chromogranin B 420–493-like immunoreactivity concentrations were found in the pituitary gland, chromogranin B 420–493 (1–17)-like immunoreactivity74.3 ± 8.5 (mean ± S.E.M.pmol/g wet wt tissue) and chromogranin B 420–493 (20–38)-like immunoreactivity2017.0 ± 142.3, followed by the hypothalamus and substantia nigra. In the spinal cord, the highest concentration was found in the sacral dorsal area. Chromogranin B 420–493-like immunoreactivity was detected in human cerebrospinal fluid, chromogranin B 420–493 (1–17)-like immunoreactivity376.7 ± 77.9 and chromogranin B 420–493 (20–38)-like immunoreactivity1174.7 ± 259.3pmol/l cerebrospinal fluid. Chromogranin B 420–493-like immunoreactivity was also found in high concentrations in the guinea-pig and rat pituitary glands, but very low chromogranin B 420–493-like immunoreactivity levels were present in different parts of the brain of both species. Gel permeation chromatography and fast protein liquid chromatography analysis of eight different regions of human CNS showed multiple chromogranin B 420–493-like immunoreactivity peaks. The profile of pituitary extracts was different from those of other parts of the CNS and the cerebrospinal fluid. The profiles of guinea-pig and rat pituitary on gel chromatography and fast protein liquid chromatography were different again from those of human CNS. Examination of subcellular fractionation of whole rat brain showed highest concentrations of chromogranin B 420–493-like immunoreactivity in the synaptosome fractions. Chromogranin B 420–493-like immunoreactivity release was stimulated from rat pituitary cells by high potassium ion concentrations. These findings show that (1) chromogranin B 420–493-like immunoreactivity is widely distributed throughout the pituitary gland and CNS of three mammalian species, with the highest concentration in the pituitary gland, and it is also present in human cerebrospinal fluid, and (2) the processing of chromgranin B in the pituitary gland may be different from that in the other area of the CNS, so that it is possible chromogranin B or its fragments may play a neuroeffector role in the mammalian CNS.