Corticotropin and cortisol responses to corticotropin-releasing factor in the chronically hypoxemic ovine fetus.
OBJECTIVE
The purpose of this study was to determine if mild hypoxemia (approximately 25% below normal) of at least 5 days' duration alters corticotropin and cortisol responses to corticotropin-releasing factor.


METHODS
We studied 14 (hypoxemic, n = 5; normoxemic, n = 9) fetuses of 135 +/- 1 (mean +/- SEM) days' gestational age. Fetuses were placed in the experimental group if arterial PO2 was < or = 16 mm Hg for 5 days. In normoxemic animals arterial PO2 was > or = 17 mm Hg. Plasma hormone responses were compared by analysis of variance.


RESULTS
Resting corticotropin levels were not different (hypoxemic 26 +/- 5 pg/ml, normoxemic 29 +/- 12 pg/ml), and corticotropin-releasing factor (530 +/- 30 ng/kg) increased (p = 0.01) corticotropin levels similarly in both groups. Basal plasma cortisol levels (hypoxemic 20 +/- 10 ng/ml, normoxemic, 30 +/- 7 ng/ml) were not significantly different. Both groups had similarly increased (p < 0.01) plasma cortisol levels after corticotropin-releasing factor administration.


CONCLUSIONS
Mild hypoxemia lasting 5 days does not significantly alter corticotropin and cortisol responses to corticotropin-releasing factor in the late-gestation ovine fetus.
Kerr
D R
DR
Department of Physiology/Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1083.
Castro
M I
MI
Valego
N K
NK
Rawashdeh
N M
NM
Rose
J C
JC
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D001158:Arteries; D002908:Chronic Disease; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005312:Fetal Blood; D005315:Fetal Diseases / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood*; D000860:Hypoxia / Q000097:blood*; D009994:Osmolar Concentration; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D012756:Sheep / Q000196:embryology
D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D010100:Oxygen; D006854:Hydrocortisone