Fenoterol treatment and desensitization of beta-adrenoceptors in rabbit foetal lung.
The foetal lung responds to beta-receptor agonists with a release of surfactant from alveolar cells. The aim of the present study was to investigate whether the administration of the betamimetic fenoterol could influence the desensitization - associated decrease of beta-adrenoreceptors in the rabbit foetal lung. With experiments on pregnant rabbits, this hypothesis was put to the test and found to be true. At a gestational age of 27-28 days, does were infused 7.5-10.0 mg of fenoterol or given Ringer's solution. The does and foetuses were sacrificed at 12 hours from the start of the infusion, and the number and affinity of beta-adrenergic receptors in lung tissues were determined by a direct binding technique using 3H-dihydroprenolol. These studies show that fenoterol can induce desensitization of beta-receptors in the foetal lung but not in the doe. Thus, it is concluded that desensitization of foetal pulmonary adrenoreceptors may result in diminished lung function after long-term treatment with beta-2 sympathicomimetics.
Falkay
G
G
Department of Obstetrics and Gynaecology, University Medical School of Szeged, Hungary.
Török
I
I
Kovács
L
L
D000818:Animals; D004082:Dihydroalprenolol / Q000378:metabolism; D005280:Fenoterol / Q000494:pharmacology*; D005333:Fetus; D007700:Kinetics; D008168:Lung / Q000187:drug effects / Q000196:embryology / Q000502:physiology*; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D012016:Reference Values
D011943:Receptors, Adrenergic, beta; D005280:Fenoterol; D004082:Dihydroalprenolol