title: Cortisol effect on atrial natriuretic factor response to hypertonic saline in fetal sheep.
abstract: Atrial natriuretic factor (ANF) is released following a variety of stimuli including hypertonicity in the fetus. To study the effect that cortisol has on fetal ANF release, seven chronically instrumented fetal sheep at gestational ages ranging from 110-132 days were studied in two experiments. In one experiment (CORTISOL), a continuous cortisol (with EtOH vehicle) infusion was maintained. In the other experiment (CONTROL), the vehicle was infused alone. Ninety minutes from the start of this infusion, a hypertonic saline bolus (12 meg/kg) was given. Osmolality, ANF, cortisol, pH, PO2, PCO2, mean arterial pressure (MAP), heart rate (HR), and hematocrit (HCT) were followed over a 120-min period. Following hypertonic saline, serum osmolality increased from 290.6 +/- 2.3 mOsm/kg to 310.4 +/- 2.5 mOsm/kg (P < 0.01). Baseline values for pH, PO2, and HCT were 7.37 +/- 0.01, 22.5 +/- 1.6 mmHg, and 33.9 +/- 1.2 respectively. Each of these variables fell following hypertonic saline infusion. MAP rose from 40.6 +/- 1.7 mmHg to 47.0 +/- 2.4 mmHg (P < 0.01). However, there were no differences between CONTROL and CORTISOL experiments in any of the above changes. Cortisol levels in the CONTROL group did not change during the course of the experiment, but in the CORTISOL group rose from 8.2 +/- 4.4 ng/ml to 33.0 +/- 9.9 ng/ml (P = 0.02). Plasma ANF levels prior to hypertonic saline were similar (124.8 +/- 17.7 pg/ml and 127.6 +/- 26.1 pg/ml) in the CONTROL and CORTISOL groups respectively and rose following hypertonic saline to a maximum of 155.3 +/- 16.6 pg/ml and 189.2 +/- 42.7 pg/ml (P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Obstetrics and Gynecology, University of Kansas School of Medicine, Kansas City 66103.
authors.forename: T L
authors.initials: TL
authors.lastname: Bennett
authors.forename: J C
authors.initials: JC
authors.lastname: Rose
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis* / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects; D006400:Hematocrit; D006854:Hydrocortisone / Q000097:blood / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010100:Oxygen / Q000097:blood; D012462:Saline Solution, Hypertonic; D012756:Sheep; D013997:Time Factors
chemical_list: D012462:Saline Solution, Hypertonic; D002245:Carbon Dioxide; D009320:Atrial Natriuretic Factor; D010100:Oxygen; D006854:Hydrocortisone