Maternal administration of glucocorticoid and thyrotropin-releasing hormone enhances fetal lung maturation in undisturbed preterm lambs.
OBJECTIVE
We hypothesized that combined treatment with glucocorticoid plus thyrotropin-releasing hormone administered to pregnant ewes with preterm gestation accelerates fetal lung maturation of undisturbed lambs better than single hormonal treatment does.


METHODS
Twenty-five pregnant ewes at 123 days of gestation were randomized to receive (1) 0.9% sodium chloride (controls), (2) betamethasone (12 mg intramuscularly every 24 hours two times), (3) thyrotropin-releasing hormone (400 micrograms intravenously every 8 hours six times), or (4) thyrotropin-releasing hormone plus betamethasone. After delivery by cesarean section at 125 days fetal lamb lung compliance and alveolar lavage phospholipid content were determined.


RESULTS
Betamethasone plus thyrotropin-releasing hormone significantly increased fetal lung compliance expressed as milliliters of air per gram of wet weight at 40 cm H2O and 5 cm H2O (0.82 +/- 0.13 and 0.35 +/- 0.10 ml/gm wet lung, respectively) versus betamethasone (0.37 +/- 0.02 and 0.07 +/- 0.02), thyrotropin-releasing hormone (0.38 +/- 0.02 and 0.14 +/- 0.03), and control (0.25 +/- 0.03 and 0.09 +/- 0.01) groups. Also, total phospholipids and saturated phosphatidylcholine concentrations in alveolar lavage were significantly higher in the combined betamethasone plus thyrotropin-releasing hormone group (27.3 +/- 4.9 and 16.9 +/- 4.3 micrograms/gm wet lung, respectively) versus betamethasone (10.9 +/- 3.5 and 6.7 +/- 2.1), thyrotropin-releasing hormone (15.2 +/- 5.6 and 7.3 +/- 2.0), and control (7.9 +/- 2.4 and 3.6 +/- 1.0) groups.


CONCLUSIONS
Combined maternal administration of betamethasone plus thyrotropin-releasing hormone improves lung maturation in undisturbed fetal lambs at 125 days' gestation more than does either hormone given alone.
Moraga
F A
FA
Departamento de Medicina Experimental, Facultad de Medicina, Universidad de Chile, Santiago.
Riquelme
R A
RA
López
A A
AA
Moya
F R
FR
Llanos
A J
AJ
D000704:Analysis of Variance; D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004359:Drug Therapy, Combination; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects; D005865:Gestational Age; D008168:Lung / Q000187:drug effects / Q000196:embryology* / Q000502:physiology; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011247:Pregnancy; D012756:Sheep; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000627:therapeutic use*
D010713:Phosphatidylcholines; D010743:Phospholipids; D013973:Thyrotropin-Releasing Hormone; D001623:Betamethasone