title: Effect of atrial natriuretic factor in rat pregnancy.
abstract: Protocols were designed to 1) identify atrial natriuretic factor (ANF) bioactivity in pregnant rats, 2) compare ANF activity in atria from gravid and virgin Sprague-Dawley animals, and 3) assess renal and vascular responsiveness to ANF during gestation. Similar quantities of ANF were extracted from atria of term gravid and age-matched controls (assayed as the natriuretic response in awake virgins). We then purified by high-performance liquid chromatography a peptide identical to the synthetic 23 amino acid atriopeptin II (AP II). With equimolar injections of ANF, gravid rats had a blunted natriuretic response (P less than 0.05). However, when dose was based on estimated extracellular volume, awake virgin and pregnant animals displayed similar highly significant dose-response curves to infused AP II (R's 0.8). When hydropenic rats were assayed, both gravid and virgins required 10 times more ANF to initiate a diuresis; dose-response curves again being similar and highly significant. Decrements in blood pressure were also similar in pregnant and nongravid animals. Thus, despite an increased intravascular volume of 70% during gestation, cardiac content of ANF and the renal and vascular responsiveness to this peptide are similar to those in virgin rats, suggesting resetting of ANF-volume relationships during pregnancy.
mesh_terms: D000818:Animals; D016275:Atrial Function; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001681:Biological Assay; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight; D005110:Extracellular Space; D005260:Female; D007668:Kidney / Q000502:physiology; D009318:Natriuresis; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D051381:Rats
chemical_list: C472610:atrial natriuretic peptide, rat; D009320:Atrial Natriuretic Factor