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Anterior Pituitary Leptin Expression Changes in Different Reproductive States: Stimulation, in vitro, by Gonadotropin Releasing Hormone (GnRH)
- Publication Year :
- 2006
-
Abstract
- This study was designed to learn more about the changes in expression of rat anterior pituitary (AP) leptin during the estrous cycle. QRT-PCR assays of cycling rat AP leptin mRNA showed 2-fold increases from metestrus to diestrus followed by an 86% decrease on the morning of proestrus. Percentages of leptin cells increased in proestrus and pregnancy to 55-60% of AP cells. Dual labeling for leptin proteins and growth hormone (GH) or gonadotropins showed that the rise in leptin protein-bearing cells from diestrus to proestrus was mainly in GH cells. Only 10-20% of leptin cells in male or cycling female rats coexpress gonadotropins. In contrast, 50-73% of leptin cells from pregnant or lactating females coexpress gonadotropins and only 19% coexpress GH, indicating plasticity in the distribution of leptin. Leptin cells expressed GnRH receptors, and estrogen and GnRH together increased the coexpression of leptin mRNA and gonadotropins. GnRH increased cellular leptin proteins three to four times and mRNA 9.8 times in proestrous rats and stimulated leptin secretion in cultures from diestrous, proestrous, and pregnant rats. These regulatory influences, and the high expression of AP leptin during proestrus and pregnancy, suggest a supportive role for leptin during key events involved with reproduction.
- Subjects :
- Leptin
Male
endocrine system
digestive, oral, and skin physiology
Estrous Cycle
Article
Rats
Gonadotropin-Releasing Hormone
Rats, Sprague-Dawley
Pituitary Gland, Anterior
Pregnancy
Animals
Lactation
Pregnancy, Animal
Female
RNA, Messenger
reproductive and urinary physiology
hormones, hormone substitutes, and hormone antagonists
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.pmid..........15b7b75d5126f895623fd4462e8eed18