Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Neonatal Lipopolysaccharide Exposure Exacerbates Stress-Induced Suppression of Luteinizing Hormone Pulse Frequency in Adulthood

Neonatal Lipopolysaccharide Exposure Exacerbates Stress-Induced Suppression of Luteinizing... Early life exposure to immunological challenge has programming effects on the adult hypothalamo-pituitary-adrenocortical axis stress responsivity, and stress is known to suppress GnRH pulse generator activity, especially LH pulses. We investigated the effects of neonatal exposure to endotoxin on stress-induced suppression of pulsatile LH secretion and the involvement of corticotropin-releasing factor (CRF) receptor mechanisms in adult rats. Pups at 3 and 5 d of age were administered lipopolysaccharide (LPS, 50 μg/kg, ip). At 12 wk of age, they were ovariectomized and implanted with sc 17β-estradiol capsules and iv cannulas. Blood samples (25 μl) were collected every 5 min for 5 h for LH measurement. After 2 h of sampling, rats were given LPS (25 μg/kg, iv). CRF and CRF-R1 and CRF-R2 receptor mRNA was determined by RT-PCR in medial preoptic area (mPOA) micropunches collected at 3 h after LPS administration. There was no difference in basal LH pulse frequency between neonatal LPS- and neonatal saline-treated controls. However, neonatal endotoxin-treated rats exhibited a significantly greater LPS stress-induced suppression of LH pulse frequency. Basal mPOA CRF-R1 expression was unchanged in neonatal LPS- and neonatal saline-treated rats. However, CRF-R1 expression was significantly increased in response to LPS stress in neonatal LPS-treated animals but not in neonatal saline-treated controls. CRF and CRF-R2 expression was unchanged in all treatment groups. These data demonstrate that exposure to bacterial endotoxin in early neonatal life programs long-term sensitization of the GnRH pulse generator to the inhibitory influence of stress in adulthood, an effect that might involve up-regulation of CRF-R1 expression in the mPOA. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Endocrinology Oxford University Press

Neonatal Lipopolysaccharide Exposure Exacerbates Stress-Induced Suppression of Luteinizing Hormone Pulse Frequency in Adulthood

Download PDF
7 pages

Loading next page...
 
/lp/oxford-university-press/neonatal-lipopolysaccharide-exposure-exacerbates-stress-induced-TArexTJPbV

References (38)

Publisher
Oxford University Press
Copyright
Copyright © 2007 by The Endocrine Society
ISSN
0013-7227
eISSN
1945-7170
DOI
10.1210/en.2007-0710
pmid
17872370
Publisher site
See Article on Publisher Site

Abstract

Early life exposure to immunological challenge has programming effects on the adult hypothalamo-pituitary-adrenocortical axis stress responsivity, and stress is known to suppress GnRH pulse generator activity, especially LH pulses. We investigated the effects of neonatal exposure to endotoxin on stress-induced suppression of pulsatile LH secretion and the involvement of corticotropin-releasing factor (CRF) receptor mechanisms in adult rats. Pups at 3 and 5 d of age were administered lipopolysaccharide (LPS, 50 μg/kg, ip). At 12 wk of age, they were ovariectomized and implanted with sc 17β-estradiol capsules and iv cannulas. Blood samples (25 μl) were collected every 5 min for 5 h for LH measurement. After 2 h of sampling, rats were given LPS (25 μg/kg, iv). CRF and CRF-R1 and CRF-R2 receptor mRNA was determined by RT-PCR in medial preoptic area (mPOA) micropunches collected at 3 h after LPS administration. There was no difference in basal LH pulse frequency between neonatal LPS- and neonatal saline-treated controls. However, neonatal endotoxin-treated rats exhibited a significantly greater LPS stress-induced suppression of LH pulse frequency. Basal mPOA CRF-R1 expression was unchanged in neonatal LPS- and neonatal saline-treated rats. However, CRF-R1 expression was significantly increased in response to LPS stress in neonatal LPS-treated animals but not in neonatal saline-treated controls. CRF and CRF-R2 expression was unchanged in all treatment groups. These data demonstrate that exposure to bacterial endotoxin in early neonatal life programs long-term sensitization of the GnRH pulse generator to the inhibitory influence of stress in adulthood, an effect that might involve up-regulation of CRF-R1 expression in the mPOA.

Journal

Endocrinology – Oxford University Press

Published: Dec 1, 2007

There are no references for this article.