Caudal brain stem plays a role in metabolic control of estrous cycles in Syrian hamsters

Schneider, Jill E.; Zhu, Yan

doi:10.1016/0006-8993(94)91182-7

Cited by 50 publications

(29 citation statements)

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“…Thus, it is tempting to speculate that AP-NTS neurons are a part of the sensing mechanism for ketone bodies under ketogenic conditions and mediate the suppression of LH secretion. This notion is well consistent with the previous studies revealing the localization of energy-sensing mech- It has been suggested that a sensing mechanism for nutritional condition exists in the lower brainstem [4,5,40], and the hindbrain region plays important roles in the nutritional regulation of physiological functions such as feeding [32] and reproduction [30,31]. In fact, neurons within the caudal hindbrain also monitor lactate utilization as an indicator of energy imbalance in the central nervous system [41].…”

Section: Discussionsupporting

confidence: 91%

“…Overall, a mechanism sensing energy substrates might be located in the hindbrain of rats. It has been suggested that a sensing mechanism for nutritional condition exists in the lower brainstem [4,5,40], and the hindbrain region plays important roles in the nutritional regulation of physiological functions such as feeding [32] and reproduction [30,31]. In fact, neurons within the caudal hindbrain also monitor lactate utilization as an indicator of energy imbalance in the central nervous system [41].…”

Section: Discussionmentioning

confidence: 99%

“…Expression of MCT1 [23][24][25] and MCT2 [24] mRNA in neonatal brains is much greater than in adult brains, which may be associated with the fact that ketone bodies synthesized by hepatic oxidation of maternal milk fat are major metabolic fuels for neonatal brain [26][27][28]. An electron microscopic study in the adult rat brain revealed that MCT1 expression increases in response to the elevated plasma levels of ketone bodies induced by a high-fat diet [29].Neurons in the area postrema and solitary tract nucleus (AP-NTS) have been demonstrated to be involved in nutritional regulation of reproduction [30,31] as well as feeding [32]. The arcuate nucleus and ventromedial hypothalamic nucleus (ARC-VMH) and the central gray and supragenual nucleus around the 4th ventricle (CG-Sge) regions have also been shown to be involved in control of reproductive function and ingestive behavior [5].…”

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confidence: 99%

“…Neurons in the area postrema and solitary tract nucleus (AP-NTS) have been demonstrated to be involved in nutritional regulation of reproduction [30,31] as well as feeding [32]. The arcuate nucleus and ventromedial hypothalamic nucleus (ARC-VMH) and the central gray and supragenual nucleus around the 4th ventricle (CG-Sge) regions have also been shown to be involved in control of reproductive function and ingestive behavior [5].…”

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confidence: 99%

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Food Deprivation Induces Monocarboxylate Transporter 2 Expression in the Brainstem of Female Rat

Matsuyama

Ohkura

Iwata

et al. 2009

Journal of Reproduction and Development

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Abstract. Ketone bodies are considered to act as a signal to suppress gonadotropin release during negative energy balance. The present study examined the effect of 48-h fasting on the mRNA expressions of monocarboxylate transporter 1 (MCT1) and MCT2, which are involved in ketone body transport, in several brain regions. Quantitative real-time RT-PCR analysis showed that the MCT2 mRNA levels were significantly increased by 48-h fasting in the area postrema-solitary tract nucleus (AP-NTS) region but not the arcuate nucleus-ventromedial hypothalamic nucleus (ARC-VMH) and central gray-supragenual nucleus around the 4th ventricle (CG-SGe) regions. Fasting did not significantly affect MCT1 mRNA expression in any of the brain areas examined. Luteinizing hormone (LH) pulse frequency significantly decreased and plasma concentrations of β-hydroxybutyric acid, a ketone body, significantly increased after 48-h fasting. The present results suggest that increased uptake of ketone bodies via MCT2 in the AP-NTS region is likely involved in the mechanism of fasting-induced suppression of LH secretion in rats. Key words: Fasting, Ketone body, Luteinizing hormone, Monocarboxylate transporter (J. Reprod. Dev. 55: [256][257][258][259][260][261] 2009) nergy balance has been reported to control pulsatile luteinizing hormone (LH) secretion [1,2]. In high-performance dairy cows, negative energy balance caused by the high-energy requirements during lactation has been suggested to be involved in the decline in LH secretion and reproductive performance [3]. Glucose sensing by the hindbrain is thought to be of particular importance in suppression of LH secretion under negative energy balance [4,5]. It is also possible that other oxidizable fuels, such as fatty acids [6,7] and ketone bodies [8], serve as metabolic signals informing the brain of nutritional conditions to induce LH suppression.Ketone bodies are produced in the liver from excess amounts of acetyl-CoA under malnutritional conditions. Under such circumstances, glucose utilization in the brain decreases, while uptake of ketone bodies into the brain increases [9][10][11]. Ketone bodies have been reported to be utilized as an energetic substitute for glucose [9,12,13]. On the other hand, ketone bodies might be a signal for the brain to induce suppression of LH secretion under negative energy balance. This is because the fourth cerebroventricular injection of 3-hydroxybutyrate, a physiological ketone body, suppressed pulsatile LH secretion in female rats [8], suggesting that ketone bodies are sensed by the hindbrain, same as glucose [14].Proton-coupled monocarboxylate transporters (MCTs) are responsible for the transport of monocarboxylates, such as ketone bodies, lactate and pyruvate, into the cell [15,16]. Of 14 distinct MCT molecules identified, MCT1 and MCT2 are the major isoforms in the rodent brain [17,18]. MCT1 is mainly expressed in microvessel endothelial cells, ependymocytes lining the cerebroventricles, glial limitans and choroid plexus epithelium [19][20][21][22], and ...

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Food Deprivation Induces Monocarboxylate Transporter 2 Expression in the Brainstem of Female Rat

Matsuyama

Ohkura

Iwata

et al. 2009

Journal of Reproduction and Development

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“…This effect is most likely due to ablation of forebrain, and not hindbrain, mechanisms. Although the AP/NTS is necessary for 2DG-induced food intake in rats (39) and estrous behavior disruption in Syrian hamsters (44), 2DG-induced torpor-like hypothermia fails to stimulate Fos-like immunoreactivity in the AP/NTS (35) and AP/NTS ablation fails to prevent 2DG-induced torporlike hypothermia (1). 2DG treatment, on the other hand, increases NPY mRNA and NPY turnover in the ARC of rats (46).…”

Section: Discussionmentioning

confidence: 99%

Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters

Pelz

Routman²,

Driscoll³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Pelz KM, Routman D, Driscoll JR, Kriegsfeld LJ, Dark J. Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters. Am J Physiol Regul Integr Comp Physiol 294: R255-R265, 2008. First published March 1, 2007 doi:10.1152/ajpregu.00387.2007.-Siberian hamsters (Phodopus sungorus) have the ability to express daily torpor and decrease their body temperature to ϳ15°C, providing a significant savings in energy expenditure. Daily torpor in hamsters is cued by winterlike photoperiods and occurs coincident with the annual nadirs in body fat reserves and chronic leptin concentrations. To better understand the neural mechanisms underlying torpor, Siberian hamster pups were postnatally treated with saline or MSG to ablate arcuate nucleus neurons that likely possess leptin receptors. Body temperature was studied telemetrically in cold-acclimated (10°C) male and female hamsters moved to a winterlike photoperiod (10:14-h light-dark cycle) (experiments 1 and 2) or that remained in a summerlike photoperiod (14:10-h light-dark cycle) (experiment 3). In experiment 1, even though other photoperiodic responses persisted, MSG-induced arcuate nucleus ablations prevented the photoperioddependent torpor observed in saline-treated Siberian hamsters. MSGtreated hamsters tended to possess greater fat reserves. To determine whether reductions in body fat would increase frequency of photoperiod-induced torpor after MSG treatment, hamsters underwent 2 wk of food restriction (70% of ad libitum) in experiment 2. Although food restriction did increase the frequency of torpor in both MSG-and saline-treated hamsters, it failed to normalize the proportion of MSGtreated hamsters undergoing photoperiod-dependent torpor. In experiment 3, postnatal MSG treatments reduced the proportion of hamsters entering 2DG-induced torpor-like hypothermia by ϳ50% compared with saline-treated hamsters (38 vs. 72%). In those MSG-treated hamsters that did become hypothermic, their minimum temperature during hypothermia was significantly greater than comparable salinetreated hamsters. We conclude that 1) arcuate nucleus mechanisms mediate photoperiod-induced torpor, 2) food-restriction-induced torpor may also be reduced by MSG treatments, and 3) arcuate nucleus neurons make an important, albeit partial, contribution to 2DG-induced torpor-like hypothermia. thermoregulation; leptin; neuropeptide Y; body mass; fat SIBERIAN HAMSTERS UNDERGO numerous physiological and behavioral changes when experiencing a winterlike photoperiod with a short photophase (SP) and low ambient temperatures (T a ), including bouts of shallow, daily torpor (e.g., Ref. 23). Daily torpor is a form of reversible hypothermia that occurs during the rest/sleep phase of the circadian cycle, coincident with the time of the circadian minimum in body temperature (T b ). In fact, it is accepted that this represents an exaggeration of the usual 1-3°C sleep-dependent decrease in T b (13, 52). During daily torpor, however, T b may ...

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Body fat and time of year interact to mediate dispersal behaviour in ground squirrels

Nunes

Garrett

et al. 1998

Animal Behaviour

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Caudal brain stem plays a role in metabolic control of estrous cycles in Syrian hamsters

Cited by 50 publications

References 16 publications

Food Deprivation Induces Monocarboxylate Transporter 2 Expression in the Brainstem of Female Rat

Food Deprivation Induces Monocarboxylate Transporter 2 Expression in the Brainstem of Female Rat

Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters

Body fat and time of year interact to mediate dispersal behaviour in ground squirrels

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