Hydra head activator-like immunoreactivity in human brain astrocytomas grade III-IV and the surrounding brain tissue.
We have developed a specific and sensitive radioimmunoassay for the hydra head activator neuropeptide (HHAP). The antibody recognizes the C-terminal portion of HHAP and shows no cross-reactivity with other neuropeptides. The assay allows measurement of HHAP-like material in tissue extracts with a minimum detectable concentration of 22 fmol/ml standard HHAP (2 fmol/tube). The concentration of immunoreactive (IR) HHAP in histopathologically characterized tissues was determined in 43 specimens from astrocytomas grade III-IV and surrounding brain tissue from 18 patients. Twenty-two control specimens of gray and white matter and five from hypothalamus were taken from 5 brains at autopsy. The concentration of IR-HHAP in the brain tumors, including the actively growing tumor front, is lower than in normal brain, and thus appears not to act as a growth factor. High performance liquid chromatography (HPLC) of extracts of hypothalamus and tumors revealed two major peaks of IR-HHAP; one eluted with the same elution volume as synthetic HHAP. HPLC of cerebral cortex extracts revealed only one major peak of IR-HHAP eluting close to the void volume, which may indicate a posttranslational processing variability of HHAP in different brain regions. By immunocytochemistry HHAP immunoreactivity was localized to the cytoplasma of neuroectodermal cells.
Ekman
R
R
Department of Psychiatry and Neurochemistry, University of Lund, Sweden.
Salford
L
L
Brun
A
A
Larsson
I
I
D000595:Amino Acid Sequence; D001932:Brain Neoplasms / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D005909:Glioblastoma / Q000032:analysis*; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000032:analysis* / Q000502:physiology; D010666:Phenylpropionates; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011863:Radioimmunoassay; D012710:Serum Albumin, Bovine / Q000276:immunology
D006133:Growth Substances; D009479:Neuropeptides; D010666:Phenylpropionates; D012710:Serum Albumin, Bovine; C008869:phloretic acid; C032522:head activator peptide; D011761:Pyrrolidonecarboxylic Acid