Journal of Reproduction and Development
Online ISSN : 1348-4400
Print ISSN : 0916-8818
ISSN-L : 0916-8818
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Acute Lipoprivation Suppresses Pulsatile Luteinizing Hormone Secretion without Affecting Food Intake in Female Rats
Mohammad SHAHABSomchai SAJAPITAKHiroko TSUKAMURAMika KINOSHITAShuichi MATSUYAMASatoshi OHKURAShunji YAMADAYoshihisa UENOYAMAHelen I'ANSONKei-ichiro MAEDA
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2006 Volume 52 Issue 6 Pages 763-772

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Abstract

The present study examined the effect of acute lipoprivation on pulsatile luteinizing hormone (LH) secretion in both normal-fat diet, ad libitum-fed and fasted female rats. To produce an acute lipoprivic condition, mercaptoacetate (MA), an inhibitor of fatty acid oxidation, was administered intraperitoneally to ad libitum-fed or 24-h fasted ovariectomized (OVX) rats with or without an estradiol (E2) implant, that produces a negative feedback effect on LH pulses. The steroid treatment was performed to determine the effect of estrogen on lipoprivic changes in LH release, because estrogen enhances fasting- or glucoprivation-induced suppression of LH pulses. Pulsatile LH secretion was suppressed by MA administration in a dose-dependent manner in the ad libitum-fed OVX and OVX+E2 rats. LH pulses were more severely suppressed in the 24-h-fasted OVX and OVX+E2 rats compared to the ad libitum-fed rats. Estrogen slightly enhanced lipoprivic suppression but the effect was not significant. In the present study, increased plasma glucose and free-fatty acid concentrations may indicate a blockade of fatty acid metabolism by the MA treatment, but food intake was not affected by any of the MA doses. Acute vagotomy did not block lipoprivic suppression of LH pulses. Thus, the present study indicates that lipid metabolism is important for maintenance of normal reproductive function even in rats fed a normal-fat diet and lipoprivation may be more critical in fasted animals that probably rely more heavily on fatty acid oxidation to maintain appropriate metabolic fuel levels. In addition, failure of blockade of lipoprivic LH inhibition by vagotomy suggests that lipoprivic information resulting in LH suppression is not transmitted to the brain via the vagus nerve.

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© 2006 Society for Reproduction and Development

この記事はクリエイティブ・コモンズ [表示 - 非営利 - 改変禁止 4.0 国際]ライセンスの下に提供されています。
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
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