Regulation of beta-adrenergic receptor-mediated processes in fetal rat lung: selective desensitization caused by chronic terbutaline exposure.

Published

Journal Article

Fetal lung beta-receptors become effectively coupled to lung fluid reabsorption and enzymes involved in surfactant synthesis on the day before birth, a period when circulating catecholamine levels are high. Accordingly, we examined the effects of repeated maternal terbutaline exposure on beta-receptor binding capabilities and beta-receptor-mediated processes in the fetal rat lung. Administration of terbutaline to pregnant rats on gestational day 17-20 produced significant reductions in beta-receptor binding to membrane preparations. Similarly, beta-receptor-mediated stimulation of adenylate cyclase activity and ornithine decarboxylase activity showed marked desensitization in the terbutaline-exposed fetuses. However, the linkage of beta-receptors to lung fluid reabsorption and phosphatidic acid phosphatase, an enzyme involved in surfactant synthesis, did not desensitize with chronic terbutaline pretreatment; both of these processes displayed the normal onset of responsiveness on gestational day 21 in the treated animals, as well as a normal magnitude of response. Hence, beta-receptor-mediated events in the developing lung may be differentially regulated during exposure to agonists, allowing the selective expression or depression of function when circulating catecholamine levels are high.

Full Text

Duke Authors

Cited Authors

  • Kudlacz, EM; Navarro, HA; Slotkin, TA

Published Date

  • August 1990

Published In

Volume / Issue

  • 14 / 2

Start / End Page

  • 103 - 108

PubMed ID

  • 1965439

Pubmed Central ID

  • 1965439

International Standard Serial Number (ISSN)

  • 0141-9846

Language

  • eng

Conference Location

  • England