Cerebrospinal Fluid and Ependymal Neurophysin

Abstract

Neurophysins are "carrier proteins" associated with vasopressin and oxytocin in the neurohypophyseal system. The release of these hormone associated proteins may serve as an indicator of posterior pituitary function. This report describes the measurement of neurophysin in human and monkey plasma and cerebrospinal fluid (CSF) by radioimmunoassay. Tissue neurophysin is also localized in monkey brain by the immunoperoxidase technique. CSF from 68 patients and five monkeys had easily measurable neurophysin in every sample. The concentration of neurophysin in CSF and in plasma of man is 5.4±0.30 ng/ml (mean and SEM) and 0.69+0.04, respectively. The two means were significantly different (P < 0.001). In paired plasma and CSF specimens which were obtained simultaneously from each of 13 human and five monkey donors, the concentrations of neurophysin in CSF were greater than those of plasma in every case (paired t test, P <0.001). Neurophysin administered intravenously to dogs did not enter CSF. Using the immunoperoxidase technique, we found neurophysin not only in the supraoptic and paraventricular nuclei, their tracts, and the posterior pituitary, but also in the specialized ependymal tanycytes of the infundibular recess of the third ventricle and in the external layer of the median eminence where capillaries drain into hypophyseal portal vessels. Neurophysin may pass from CSF to portal vessels via tanycytes in a manner similar to that postulated for releasing factors.

Contractile effects of perivascularly applied vasopressin on the pial artery of the cat brain.

“…The origin of the CSF vasopressin is considered to be hypothalamic vasopressin-containing neurones (Brownfield & Kozlowski, 1977;Buijs, Swaab, Dogterom & Van Leeuwen, 1978;Robinson & Zimmerman, 1973). Subependymal localization of vasopressin-or neurophysin-containing fibres or endings (Brownfield & Kozlowski, 1977;Buijs et al 1978;Robinson & Zimmerman, 1973) may indicate transport of vasopressin into the cerebral ventricles through the ependyma (Kobayashi, Matsui & Ishii, 1970;Rodriguez, 1976), or into the CSF-filled perivascular spaces, presumably those around veins (Rennels, Gregory, Blaumanis, Fujimoto & Grady, 1985), by bulk flow of interstitial fluid (Cserr, Cooper & Milhorat, 1977). Vasopressin so secreted into the ventricles and into the perivascular spaces may then circulate through the ventricles and subarachnoid spaces to gain access to the pial arteries and further to the penetrating arteries through the perivascular spaces (Rennels et al 1985).…”

Pituitary Portal Plasma Levels of Oxytocin during the Estrous Cycle, Lactation, and Hyperprolactinemia

“…It has been shown that a significant amount of OT is present in the cerebrospinal fluid (CSF) and in tanycytes lining the floor of the third ventricle. [46][47][48] However, OT levels in the CSF are too low to significantly contribute to the relatively high OT levels in pituitary portal blood. Horn et al have recently presented evidence that OT from the cut axons of the supraoptico-hypophysial tract does not significantly contribute to the high neuropeptide level in pituitary portal plasma following sectioning of the pituitary stalk.…”

Microvasculature as studied by the microvascular corrosion casting/scanning electron microscope method. I. Endocrine and digestive system.

“…It has been demonstrated that mammalian CSF contains numerous bioactive peptides such as vasopressin, neurophysin, TRH, lutenizing hormone releasing hormone, somatostatin, angiotensin, ACTH, growth hormone, TSH, prolactin, and sleep factors (ISHIKAWA, 1973;KNIGGE and JOSEPH, 1974;HELLER et al, 1968;PAVEL, 1973;ROBINSON and ZIMMERMAN, 1973;ALLEN et al, 1974;PAPPENHEIMER et al, 1967). Investigations into the median basal hypothalmus using tracers and labeled hormones have suggested that bio-active substances might be transported into the portal system via tanycytes and thus might influence the activity of the adenohypophyseal cells (SCOTT et al, 1974).…”