Premium
Combined postnatal estradiol and progesterone treatment improves hypoxic ventilatory response in rat pups
Author(s) -
Lefter Raluca,
Morency CatherineEve,
Doan Van Diep,
Joseph Vincent
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1215-b
Subject(s) - carotid body , medicine , endocrinology , hypoxia (environmental) , plethysmograph , peripheral , ventilation (architecture) , respiratory minute volume , respiratory rate , fetus , respiratory system , body weight , chemoreceptor , biology , chemistry , pregnancy , heart rate , carotid arteries , receptor , organic chemistry , oxygen , mechanical engineering , blood pressure , engineering , genetics
Fetuses are exposed to very‐high levels of estradiol (E 2 ) and progesterone (P), which may play important developmental roles. Since preterm neonates are chronically deprived from placental E 2 and P and exhibit specific disorders of peripheral chemoreceptor functions, our hypothesis is that E 2 +P improves respiratory chemoreflexes in newborn rats. At birth lactating female rats were implanted with osmotic pumps delivering E 2 +P (7 and 70 μg/day) at a regular flow rate. Minute ventilation was assessed in 10‐day‐old rats by whole body plethysmography in normoxia and hypoxia (10%O 2 – 30 minutes) and carotid body (CB) volume assessed by tyrosine hydroxylase staining on serial slices. E 2 +P male pups had a reduced body weight (−20%) and rectal temperature (−1°C) compared to Veh. In hypoxia, minute ventilation increased by 19% in Veh pups (n=11) and by 58% in E 2 +P pups (n=12). TH positive tissue occupied 33% of the CB in Veh vs. 38% in E 2 +P pups, and the volume (reported to body weight) of the carotid body was 5,29 in E 2 +P (n=3) vs. 3,40x105 μm 3 /g in Veh pups (n=4). These results suggest that E 2 +P accelerate the normal development of peripheral chemoreceptors in newborn mammals. Founded by the hospital for sick children foundation, FRSQ and CIHR.