Substance P in human adrenal medulla and in sympathetic tumours

Using radioimmunoassay for substance P (SP), we have detected SP-like immunoreactivity in human adrenal medulla obtained at autopsy from 12 subjects. The mean SP content was 2.2 ng/g wet tisuse. In one phaeochromocytoma, SP was undetectable and there was no concentration gradient of SP between the effluent and affluent tumour vessels. In one murine neuroblastoma cell line, SP was undetectable.