EUROP. J. OBSTET. GYNEC. REPROD. BIOL., 1977,7/6, 0 Elsevier/North-Holland Biomedical Press

357-358

Orciprenaline and fetal lung maturation in rabbits L. Cabero, J.R. Alemany, M. Quflez, R. Riera, E. Navarro, A. Torner, P. DurBn&lnchez and J. Esteban-Altirriba Servicio de Obstetriciay Ginecologia, Hospital de la Santa Cruz y San Pablo, Facultad de Medicina, UniversidadAutbnoma, and Institute de Medicina Expen’mental, Laboratorio Boehringer Sohn Ingelheim, Barcelona, Spain

CABERO, L., ALEMANY, J.R., QUILEZ, M., RIERA, R., NAVARRO, E., TORNER, A., DURAN-SANCHEZ, P. and ESTEBANALTIRRIBA, J. (1977): Orciprenaline and fetal lung maturation in rabbits. Europ. J. Obstet. Gynec. reprod. Biol., 716, 357-358. The palmitic and stearic acids and the palmitic/stearic ratio in fetal rabbit lungs were studied after orciprenaline administration to the mother from the 26th to the 31st day of gestation. The results were significantly higher in the treated groups than in the control group for the palmitic acid and palmitic/stearic ratio. palmitic acid; stearic acid; P/S ratio; betamimetic drugs

with two randomized groups was made. In the first group (control group) there were 7 rabbits and 72 fetuses and in the second group (treated group) there were 9 rabbits and 47 fetuses. Orciprenaline was administered intramuscularly to the second group from 26 to 31 days of gestation at the dosage of 60 mg/kg/day. Saline solution was administered intramuscularly as a placebo to the first group. The fetuses were extracted by the abdominal route, before onset of labor, on the 31st day of gestation. The lungs were extracted and washed in saline solution, weighed, and afterwards homogenized with 10 ml of distilled water. The extraction of lipids, hydrolysis and the methylation of fatty acids were as follows: 3 ml of chloroform-methanol (2 : 1, v/v) was added to 1 ml of homogenized lung which was shaken for 10 min and centrifuged; 0.5 ml of the lower chloroformic stratum was transferred to another tube to which 0.5 ml of hydropic sodium in methanol solution at 2% was added. It was heated to 80°C for 10 min. The free fatty acids were rnethylated with 0.5 ml of boron trifluoridemethanol at 20% and 0.1 ml of methylic ester of margaric acid in chloroform solution (111 mg/200 ml)

Introduction

The usefulness of betamimetic agents in the treatment of threatened premature labor as well as in the treatment of intrapartum fetal distress has been widely proved (Yo Le Sian, Thiery, Brosens, Baumgarten, Esteban-Altirriba, Gamissans, Flynn and Van Strik, 1972; Esteban-Altirriba, Gamissans, Duran-Sanchez, Calaf and Retie, 1972). There are some suggestions that these drugs can act on fetal lung maturation (Boog, Ben Brahim and Gandar, 1975; Cabero, Quflez, Escribano, Calaf, Giralt, Duran-Sanchez and EstebanAltirriba, 1976). In this experimental work we have studied the eventual influence of a betamimetic agent (orciprenaline) on the palmitic (P) and stearic (S) acids and the palmitic/stearic (P/S) ratio values of fetal rabbit lung.

Material and methods

The study was made with 16 rabbits (Valencian giant) of known gestational age. A double blind study 3.57

L. Cobero et al.: Orciprenaline and fetal lung maturation in rabbits

358 TABLE I

Results of fatty acids (mg/lOO ml) and P/S ratio in control and orciprenaline groups and statistical comparisons Control

Pahnitic acid Stearic acid P/S ratio

Orciprenaline P

n

Mean f SD

n

Mean + SD

(51-2

t

12 69 69

2.93 f 0.56 0.59 f 0.08 5.07 + 0.81

47 47 47

3.66 + 0.58 0.58 +O.ll 6.37 + 0.98

0.1073 0.0187 0.1730

6.8004 0.5 348 7.5145

which was used as an internal pattern. It was cooled in an ice bath and then 3 ml of a sodium chlorine solution plus 3 ml of petroleum spirit 40%6O’C were added. It was shaken for 10 min and centrifuged. Following this, the upper ethereal stratum was separated; 0.5 ml of petroleum spirit 40-60” was added, and once again the upper ethereal stratum was separated and joined to the previous one. The ether extract was evaporated by steam in the Rotavapor at 50°C. The residue was redissolved in 0.1 ml of chloroform; 1S-2 ml was processed by gas chromatography in the Hewlett-Packard 5720A. The quantification was determined by a Hewlett-Packard 33804, using the internal standard method.

Results

Table I shows the mean and standard deviations of the mean of palmitic and stearic acids and the P/S ratio of each group after orciprenaline administration, as well as the statistical comparisons.

Comments

The results show that orciprenaline provokes a significant increase of palmitic acid and of the P/S ratio in fetal rabbit lung before labor. Previously, Gamissans, Corominas, Pascual, Iglesias-Cortit, Caiias and Cuyris (1974) had found a significant increase in the L/S ratio in human amniotic fluid after ritodrine administration to the mother. Boog et al. (1975) and Cabero et al. (1976) found that the incidence of RDS in the human premature

Orciprenaline and fetal lung maturation in rabbits.

EUROP. J. OBSTET. GYNEC. REPROD. BIOL., 1977,7/6, 0 Elsevier/North-Holland Biomedical Press 357-358 Orciprenaline and fetal lung maturation in rabbi...
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