Morphological and functional alterations in the adenohypophysis in cases of brain death

In order to examine the function of the adenohypophysis during brain death, levels of adrenocorticotropic hormone (ACTH), growth hormone (GH), and thyroid stimulating hormone (TSH) were investigated during forensic autopsy. Cases examined were those of brain death (n = 12; within 24 h postmortem; time to cardiac death after cerebral death was diagnosed, approximately 4–25 days), including those in which the cause of death was head injury (subdural hematoma or brain contusion, n = 10) and asphyxia (strangulation, n = 2). The concentrations of ACTH and TSH were measured by enzyme chemiluminescent immunoassay (ECLIA), and that of GH by radioimmunoassay (RIA). The immunoreactivities of ACTH, GH, and TSH in the adenohypophysis were observed and analyzed with electron microscopy. Morphological studies revealed partial necrosis of the central anterior lobe, but preservation of its periphery. Immunohistochemical staining revealed the appearance of peripheral adenohypophysis with each hormone. Ultrastructural findings for the pituitary and hypothalamus indicated swelling of the mitochondria and dilation of both the smooth endoplasmic reticulum and Golgi apparatus. Furthermore, in most cases, concentrations of the anterior pituitary hormones in the serum and cerebrospinal fluid (CSF) were generally within the clinical reference range. These results indicate that the pituitary is partially preserved after brain death.