Effects of leptin on fetal plasma adrenocorticotropic hormone and cortisol concentrations and the timing of parturition in the sheep

Yuen, B. S. J. and Owens, P. C. and Symonds, M. E. and Keisler, D. H. and McFarlane, J. R. and Kauter, K. G. and McMillen, I. C. (2004) Effects of leptin on fetal plasma adrenocorticotropic hormone and cortisol concentrations and the timing of parturition in the sheep. Biology of Reproduction, 70 (6). pp. 1650-1657. ISSN 0006-3363

Abstract

We investigated whether leptin can suppress the prepartum activation of the fetal hypothalamus-pituitary-adrenal (HPA) axis and delay the timing of parturition in the sheep. First, we investigated the effects of a 4-day intravascular infusion of recombinant ovine leptin (n = 7) or saline (n = 6) on fetal plasma adrenocorticotropic hormone (ACTH) and cortisol concentrations, starting from 136 days gestation (i.e., at the onset of the prepartum activation of the fetal HPA axis. The effects of a continuous intrafetal infusion of leptin (n = 7) or saline (n = 5) from 144 days gestation on fetal plasma ACTH and cortisol concentrations and the timing of delivery were also determined in a separate study. There was an increase in fetal plasma ACTH (P < 0.01) and cortisol (P < 0.001) concentrations when saline was infused between 136-137 and 140-141 days gestation. Plasma ACTH and cortisol concentrations did not rise, however, when leptin was infused during this period of gestation. When leptin was infused after 144 days gestation, there was no effect of a 4- to 5-fold increase in circulating leptin on fetal ACTH concentrations. In contrast, leptin infusion from 144 days gestation suppressed (P < 0.05) fetal plasma cortisol concentrations by around 40% between 90 and 42 h before delivery. There was no difference, however, in the length of gestation between the saline- and leptin-infused groups (saline infused, 150.2 ± 0.5 days; leptin infused, 149.8 ± 1.0 days). In saline-infused fetuses, there was a significant negative relationship between the plasma concentrations of cortisol (y) and leptin (x) between 138 and 146 days gestation (y = 81.4 - 7.7x, r = 0.38, P < 0.005). This study provides evidence for an endocrine negative feedback loop between leptin and the HPA axis in fetal life.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to paper due to publisher's copyright restrictions.
Depositing User: Ms Debbie White
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 02 May 2010 12:56
Last Modified: 18 Oct 2013 01:45
Uncontrolled Keywords: adrenal; cortisol; leptin; pregnancy; animal experiment; corticotropin blood level; delivery; fetus; gestational age; hydrocortisone blood level; hypothalamus hypophysis adrenal system; negative feedback; nonhuman; pregnancy; sheep
Fields of Research (FOR2008): 06 Biological Sciences > 0606 Physiology > 060699 Physiology not elsewhere classified
07 Agricultural and Veterinary Sciences > 0702 Animal Production > 070204 Animal Nutrition
07 Agricultural and Veterinary Sciences > 0702 Animal Production > 070206 Animal Reproduction
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Identification Number or DOI: doi: 10.1095/biolreprod.103.025254
URI: http://eprints.usq.edu.au/id/eprint/7760

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