title: Release of atrial natriuretic factor from intact and hypophysectomized rat hypothalamic expiants.
abstract: Abstract Experiments examined release of atrial natriuretic factor (ANF), measured by radioimmunoassay, from acutely prepared explants of rat hypothalamus maintained in vitro by intra-arterial perfusion of artificial cerebrospinal fluid. Perfusates collected from intact preparations contained 6.1 +/- 0.6 pg (mean +/- SEM) of ANF per 2-min sample. Following a 3-min infusion of noradrenaline (60 muM), ANF release increased significantly (P<0.05) to 11.4+/-1.4 pg/sample. Media collected from hypophysectomized preparations showed the same basal ANF release (6.8 +/- 0.9 pg/sample) as intact preparations, but demonstrated no significant increase after noradrenaline infusions. Levels of spontaneous ANF release were not appreciably affected by the absence of the paraventricular nuclei and/or the anteroventral third ventricle area. Extracted material from the perfusate by reverse-phase high performance liquid chromatography revealed two main peaks of immunoreactive ANF: a small molecular weight form that coeluted with synthetic ANF (99-126) and with similar biological activity in a radioreceptor assay, and a larger molecular weight form with the same elution profile as the ANF (1-126) prohormone. These observations indicate that the ANF released from perfused rat hypothalamic explants contains distinct contributions from the hypothalamus (sites undetermined) and the neurointermediate lobe.
authors.affiliation: McGill Center for Research in Neuroscience, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Nissen
authors.forename: J
authors.initials: J
authors.lastname: Gutkowska
authors.forename: L P
authors.initials: LP
authors.lastname: Renaud