In vivo effects of corticotropin-releasing factor in pregnant rats

V. Jain, S. Q. Shi, Y. P. Vedernikov, G. R. Saade, K. Chwalisz, R. E. Garfield

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

OBJECTIVES: Our purpose was to study the effects of corticotropin- releasing factor on (1) maternal blood pressure (2) uterine vasculature, and (3) parturition in pregnant rats. STUDY DESIGN: infusion minipumps containing vehicle, corticotropin-releasing factor, or α-helical corticotropin- releasing factor 9-41 (corticotropin-releasing factor receptor antagonist) were inserted subcutaneously in timed pregnant rats on day 16 of gestation. Systolic blood pressure was measured daily by the tail-cuff method. The time of onset of labor was determined and the newborn pups were weighed. Circulating levels of corticotropin-releasing factor were measured in untreated controls by radioimmunoassay. Relaxant responses to corticotropin- releasing factor were studied in isolated segments of uterine artery from late (day 18) and term (day 22) pregnant rats mounted in a wire myograph. RESULTS: The blood pressure was decreased by corticotropin-releasing factor and increased by α-helical corticotropin-releasing factor 9-41 (p<0.05). The time of onset of labor was not affected by either treatment. Pup weight was decreased by corticotropin-releasing factor (p < 0.05). Circulating levels of corticotropin-releasing factor (immunoreactive) were not changed in pregnancy. In vitro, corticotropin-releasing factor caused relaxation of the uterine artery in a concentration-dependent manner and the relaxation was decreased at term compared with late pregnancy (p < 0.05). CONCLUSIONS: Endogenously produced corticotropin-releasing factor lowers blood pressure during pregnancy in rats. It is a relaxant of uterine vasculature and this effect is decreased at term. It does not play an essential role in the initiation of labor in rats.

Original languageEnglish (US)
Pages (from-to)186-191
Number of pages6
JournalAmerican journal of obstetrics and gynecology
Volume178
Issue number1 I
DOIs
StatePublished - Jan 1 1998

Keywords

  • Blood pressure
  • Corticotropin-releasing factor
  • Labor
  • Pregnant rat
  • Uterine artery

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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