Effects of Betamethasone and Thyroid Hormone on Fetal Rat Lung Maturation in vivo

Abstract

We studied the effect of maternal administration at various intervals of betamethasone, triiodothyronine (T3), or both, on fetal rat lung maturation. T(3) alone did not enhance choline incorporation to phosphatidylcholine by 20-day fetal lung expiants, or morphometric lung maturation. Betamethasone, and betamethasone plus T(3), increased both of those parameters over control and T(3) values. However, addition of T(3) offered no advantage over administration of betamethasone alone. Significant enhancement of morphometric lung maturation was already present after only 24 h of exposure to betamethasone, or to the combination of hormones. However, choline incorporation to phosphatidylcholine only increased significantly by 36 h of exposure to betamethasone with or without T(3).

Neonatal Exposure to Fenoterol and Betamethasone: Effects on the Behavioral Development in the Rat

“…A therapeutic dose for a 250-g rat on the basis of a human weight equivalent for surface area (Harwood, 1963) would be twice 1.1 mg/kg. In rats, a sufficient surfactant-inducing effect has indeed been observed at dosage levels of 1 mg/kg applied at gestational days 16 and 17 (Pfannschmidt et al, 1983) or gestational days 18 and 19 (Moya et al, 1992), respectively. Since the fetal BET serum levels reach about one third of the maternal values (Ballard et al, 1975), a BET dose of 0.3 mg/kg on PNDs 4 and 5 was given.…”