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Neonatal nicotine exposure alters leptin signaling in the hypothalamus–pituitary–thyroid axis in the late postnatal period and adulthood in rats
Postnatal nicotine exposure causes precocious primary hypothyroidism and programs for overweight, hyperleptinemia and secondary hypothyroidism in adulthood. As leptin and thyroid hormones share the ability to increase energy expenditure, we studied the effects of maternal nicotine exposure during la...
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Published in: | Life sciences (1973) 2010-07, Vol.87 (5), p.187-195 |
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Main Authors: | , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Postnatal nicotine exposure causes precocious primary hypothyroidism and programs for overweight, hyperleptinemia and secondary hypothyroidism in adulthood. As leptin and thyroid hormones share the ability to increase energy expenditure, we studied the effects of maternal nicotine exposure during lactation on the leptin signaling in the hypothalamus–pituitary–thyroid axis of suckling and adult offspring.
Two days after delivery, osmotic minipumps were implanted in lactating rats, and nicotine (NIC, 6
mg/kg/day s.c.) or saline (C) was administered for 14
days. Offspring were killed at 15 and 180
days-old. Proteins belonging to leptin signaling were analyzed by Western blot. Significant differences had p
<
0.05.
In the hypothalamus, NIC offspring showed higher OB-R and pSTAT-3 content (+
58%,+1.34x) at 15
days, and lower OB-R, JAK-2 and pSTAT-3 (−61%, −42%, −56%) at 180
days. In the pituitary gland, NIC offspring showed lower JAK-2 content (−52%) at 15
days, but no differences in adulthood. In the thyroid gland, the NIC group presented lower OB-R, JAK-2 and STAT-3 (−44%, −50%, −47%) and higher pSTAT-3 expression (+
80%) at 15
days. At 180
days-old, NIC offspring presented higher thyroid OB-R (+
1.54x) and lower pSTAT-3 content (−34%).
Neonatal primary hypothyroidism induced by maternal nicotine exposure during lactation may be partially explained by decreased leptin signaling in the thyroid, though the early stimulation of the central leptin pathway did not prevent the thyroid dysfunction. Long-term effects of postnatal nicotine exposure on leptin signaling in the hypothalamus and thyroid appear to involve central and peripheral leptin resistance in adulthood. |
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ISSN: | 0024-3205 1879-0631 |
DOI: | 10.1016/j.lfs.2010.06.012 |