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Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects.

Publication ,  Journal Article
Auman, JT; Seidler, FJ; Slotkin, TA
Published in: Am J Physiol Regul Integr Comp Physiol
October 2001

Terbutaline (Ter), a beta(2)-adrenergic agonist used in preterm labor, stimulates fetal beta-adrenoceptors (beta-ARs). We administered Ter to pregnant rats on gestational days 17-20 and examined beta-ARs and adenylyl cyclase (AC) signaling in heart and liver. Ter produced less downregulation of cardiac beta-ARs than in adults, despite a higher proportion of the beta(2)-subtype, and failed to elicit desensitization of the receptor-mediated AC response. AC stimulants acting at different points indicated an offsetting of homologous desensitization at the level of the beta-AR by heterologous sensitization at the level of AC: induction of total AC catalytic activity and a shift in the catalytic profile or AC isoform. In fetal liver, Ter produced downregulation of beta-ARs, in keeping with the predominance of the beta(2)-subtype; hepatic receptor downregulation was equivalent in fetus and adult. Nevertheless, there was still no desensitization of beta-AR-mediated AC responses and again AC was induced. Our results indicate that, unlike in the adult, fetal beta-AR signaling is not desensitized by beta-agonists and, in fact, displays heterologous sensitization, thus sustaining responses during parturition. At the same time, the inability to desensitize beta-AR AC responses may lead to disruption of cardiac, hepatic, or neural cell development as a consequence of tocolytic therapy with beta-agonists.

Duke Scholars

Published In

Am J Physiol Regul Integr Comp Physiol

DOI

ISSN

0363-6119

Publication Date

October 2001

Volume

281

Issue

4

Start / End Page

R1079 / R1089

Location

United States

Related Subject Headings

  • Terbutaline
  • Signal Transduction
  • Receptors, Adrenergic, beta
  • Rats
  • Pregnancy
  • Physiology
  • Organ Size
  • Myocardium
  • Maternal-Fetal Exchange
  • Male
 

Citation

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MLA
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Auman, J. T., Seidler, F. J., & Slotkin, T. A. (2001). Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects. Am J Physiol Regul Integr Comp Physiol, 281(4), R1079–R1089. https://doi.org/10.1152/ajpregu.2001.281.4.R1079
Auman, J. T., F. J. Seidler, and T. A. Slotkin. “Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects.Am J Physiol Regul Integr Comp Physiol 281, no. 4 (October 2001): R1079–89. https://doi.org/10.1152/ajpregu.2001.281.4.R1079.
Auman JT, Seidler FJ, Slotkin TA. Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects. Am J Physiol Regul Integr Comp Physiol. 2001 Oct;281(4):R1079–89.
Auman, J. T., et al. “Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects.Am J Physiol Regul Integr Comp Physiol, vol. 281, no. 4, Oct. 2001, pp. R1079–89. Pubmed, doi:10.1152/ajpregu.2001.281.4.R1079.
Auman JT, Seidler FJ, Slotkin TA. Regulation of fetal cardiac and hepatic beta-adrenoceptors and adenylyl cyclase signaling: terbutaline effects. Am J Physiol Regul Integr Comp Physiol. 2001 Oct;281(4):R1079–R1089.

Published In

Am J Physiol Regul Integr Comp Physiol

DOI

ISSN

0363-6119

Publication Date

October 2001

Volume

281

Issue

4

Start / End Page

R1079 / R1089

Location

United States

Related Subject Headings

  • Terbutaline
  • Signal Transduction
  • Receptors, Adrenergic, beta
  • Rats
  • Pregnancy
  • Physiology
  • Organ Size
  • Myocardium
  • Maternal-Fetal Exchange
  • Male