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Uenoyama Y, Inoue N, Tsukamura H. Kisspeptin and lactational anestrus: Current understanding and future prospects. Peptides 2023; 166:171026. [PMID: 37230188 DOI: 10.1016/j.peptides.2023.171026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
Lactational anestrus, characterized by the suppression of pulsatile gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release, would be a strategic adaptation to ensure survival by avoiding pregnancy during lactation in mammals. In the present article, we first provide a current understanding of the central regulation of reproduction in mammals, i.e., a fundamental role of arcuate kisspeptin neurons in mammalian reproduction by driving GnRH/LH pulses. Second, we discuss the central mechanism inhibiting arcuate Kiss1 (encoding kisspeptin) expression and GnRH/LH pulses during lactation with a focus on suckling stimulus, negative energy balance due to milk production, and the role of circulating estrogen in rats. We also discuss upper regulators that control arcuate kisspeptin neurons in rats during the early and late lactation periods based on the findings obtained by a lactating rat model. Finally, we discuss potential reproductive technology for the improvement of reproductive performance in milking cows.
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Affiliation(s)
- Yoshihisa Uenoyama
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Naoko Inoue
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Choo E, Koh A, Goodman J, Bushnell J, Mielke-Maday H, Merte B, Dando R. Decrease in sweet taste response and T1R3 sweet taste receptor expression in pregnant mice highlights a potential mechanism for increased caloric consumption in pregnancy. Physiol Behav 2020; 228:113191. [PMID: 33007356 DOI: 10.1016/j.physbeh.2020.113191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 08/11/2020] [Accepted: 09/28/2020] [Indexed: 01/22/2023]
Abstract
While much is known on how the maternal diet affects offspring fitness, less is known on the role of taste in guiding and promoting food intake during this crucial period. Women have intense food cravings and exhibit altered taste preferences during pregnancy, however the mechanistic details underlying these changes are presently unclear. We performed longitudinal brief-access taste testing in female mice before, during, and after pregnancy, along with quantitative PCR on taste buds and morphological analysis of taste tissues from pregnant and non-pregnant mice. Sucrose licking response decreased progressively during pregnancy compared to that prior to mating, with partial recovery in the post-partum period. No change in taste morphology was evident between pregnant and non-pregnant mice, however a notable decrease in T1R3 sweet taste receptor mRNA expression was recorded in pregnant dams. We conclude that altered taste preferences during pregnancy likely result from changes in the expression profile of taste buds in the mother, which may promote a less healthy diet while expecting.
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Affiliation(s)
- Ezen Choo
- Biomedical & Biological Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853
| | - Anna Koh
- Department of Food Science, Cornell University, Ithaca, NY 14853
| | - Jason Goodman
- Department of Food Science, Cornell University, Ithaca, NY 14853
| | | | | | - Bryan Merte
- College of Arts and Sciences, Cornell University, Ithaca, NY 14853
| | - Robin Dando
- Department of Food Science, Cornell University, Ithaca, NY 14853.
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3
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Kokay IC, Grattan DR, Murray JF. Prolactin maintains transient melanin-concentrating hormone expression in the medial preoptic area during established lactation. J Neuroendocrinol 2020; 32:e12827. [PMID: 31917877 DOI: 10.1111/jne.12827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/17/2019] [Accepted: 01/07/2020] [Indexed: 01/18/2023]
Abstract
A population of neurones in the medial part of the medial preoptic area (mPOA) transiently express melanin-concentrating hormone (MCH) in mid to late lactation in the rat, and this expression disappears on weaning. Prolactin is known to mediate many of the physiological adaptations that occur within the dam associated with lactation and the mPOA is well endowed with prolactin receptors (Prlr); hence, we hypothesised that these transiently MCH-expressing cells may be regulated by prolactin. By in situ hybridisation, we show that approximately 60% of the cells expressing prepro-MCH (Pmch) mRNA in the medial part of the mPOA on day 19 of lactation also express Prlr mRNA. To demonstrate that these transiently MCH-expressing cells can acutely respond to prolactin, dams were treated with bromocriptine on the morning of day 19 of lactation and then given vehicle or prolactin 4 hours later. In the prolactin-treated animals, over 80% of the MCH-immunopositive cells were also immunopositive for phosphorylated signal transducer and activator of transcription 5, an indicator of prolactin receptor activation: double immunopositive cells were rare in vehicle-treated animals. Finally, the effect of manipulating the circulating concentrations of prolactin on days 17, 18 and 19 on the number of MCH-immunopositive cells on day 19 was determined. Reducing circulating concentrations of prolactin over days 17, 18 and 19 of lactation with or without a suckling stimulus resulted in a reduction (P < 0.05) in the number of MCH-immunopositive cells in the medial part of the mPOA on day 19 of lactation. Further research is required to determine the functional role(s) of these prolactin-activated transiently MCH-expressing neurones; however, we suggest the most likely role involves adaptations in maternal metabolism to support the final week of lactation.
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Affiliation(s)
- Ilona C Kokay
- Department of Anatomy, School of Biomedical Sciences, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - David R Grattan
- Department of Anatomy, School of Biomedical Sciences, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - Joanne F Murray
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Faculty of Science and Technology, University of Westminster, London, UK
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The weaning period promotes alterations in the orexin neuronal population of rats in a suckling-dependent manner. Brain Struct Funct 2018; 223:3739-3755. [DOI: 10.1007/s00429-018-1723-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 07/07/2018] [Indexed: 10/28/2022]
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Alvisi RD, Diniz GB, Da-Silva JM, Bittencourt JC, Felicio LF. Suckling-induced Fos activation and melanin-concentrating hormone immunoreactivity during late lactation. Life Sci 2016; 148:241-6. [PMID: 26874026 DOI: 10.1016/j.lfs.2016.02.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 01/15/2023]
Abstract
AIMS Melanin-concentrating hormone (MCH) is implicated in the control of food intake, body weight regulation and energy homeostasis. Lactation is an important physiological model to study the hypothalamic integration of peripheral sensory signals, such as suckling stimuli and those related to energy balance. MCH can be detected in the medial preoptic area (MPOA), especially around the 19th day of lactation, when this hormone is described as displaying a peak synthesis followed by a decrease after weaning. The physiological significance of this phenomenon is unclear. Therefore, we aimed to investigate hypothalamic changes associated to sensory stimulation by the litter, in special its influence over MCH synthesis. MAIN METHODS Female Wistar rats (n=56) were euthanized everyday from lactation days 15-21, with or without suckling stimulus (WS and NS groups, respectively). MCH and Fos immunoreactivity were evaluated in the MPOA and lateral and incerto-hypothalamic areas (LHA and IHy). KEY FINDINGS Suckling stimulus induced Fos synthesis in all regions studied. An increase on the number of suckling-induced Fos-ir neurons could be detected in the LHA after the 18th day. Conversely, the amount of MCH decreased in the MPOA from days 15-21, independent of suckling stimulation. No colocalization between MCH and Fos could be detected in any region analyzed. SIGNIFICANCE Suckling stimulus is capable of stimulating hypothalamic regions not linked to maternal behavior, possibly to mediate energy balance aspects of lactation. Although dams are hyperphagic before weaning, this behavioral change does not appear to be mediated by MCH.
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Affiliation(s)
- R D Alvisi
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, Brazil
| | - G B Diniz
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - J M Da-Silva
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - J C Bittencourt
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; Center for Neuroscience and Behavior, Institute of Psychology, University of São Paulo, Sao Paulo 05508-030, Brazil
| | - L F Felicio
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, Brazil.
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Abizaid A, Schiavo L, Diano S. Hypothalamic and pituitary expression of ghrelin receptor message is increased during lactation. Neurosci Lett 2008; 440:206-10. [PMID: 18572316 DOI: 10.1016/j.neulet.2008.05.105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 05/10/2008] [Accepted: 05/29/2008] [Indexed: 01/22/2023]
Abstract
In the lactating rat there is a dramatic increase in food intake that peaks at around day 15 postpartum, a time when pups are near weaning age, yet still fully dependant on maternal nourishment. We examined whether the orexigenic hormone ghrelin plays a role in increasing food intake during lactation. To do this, we compared plasma levels ghrelin, as well as brain and pituitary expression of the growth hormone secretagogue receptor (GHS-R 1a) rats in one of three groups: (1) dams whose litters were removed the day after giving birth (non-lactating); (2) dams whose litters were removed on day 13 postpartum (litter removed), and dams allowed keeping their litters (lactating). On day 15 postpartum, all dams were decapitated and trunk blood collected for plasma analysis of active ghrelin levels. Also, brain and pituitaries were collected and snap frozen using liquid nitrogen and stored at -80 degrees C before mRNA extraction and RT-PCR analysis. Results show no differences in ghrelin concentrations between lactating and non-lactating rats. Hypothalamic and pituitary expression of GHS-R 1a, however, was significantly increased in lactating animals compared to non-lactating animals. Interestingly, litter removed dams had higher levels of plasma ghrelin concentrations than either lactating or non-lactating females. Furthermore, GHS-R mRNA expression in these animals remained elevated in the pituitary but not the hypothalamus. These data suggest that the hypothalamus and pituitary of lactating rats are more sensitive to the effects of ghrelin, and that hypothalamic sensitivity to ghrelin depends on the presence of a suckling litter.
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Affiliation(s)
- A Abizaid
- Institute for Neuroscience, Carleton University, Ottawa, Ontario, Canada K1S 5B6.
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7
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Abstract
The nutritional needs of developing young place a large energetic demand on lactating females. In this paper some of the mechanisms through which lactating rats meet these demands are described. Emphasis is placed on the mechanisms that drive increased food intake in suckled rats that are independent of milk delivery and negative energy balance. Evidence is presented to suggest that prolactin (PRL), released from the pituitary in response to suckling stimulation, acts centrally to stimulate food intake during lactation. Brain areas in which PRL may act to stimulate food intake as well as its interactions with other hormones and neuropeptides involved in energy balance are discussed.
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Affiliation(s)
- Barbara Woodside
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, Quebec, Canada.
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Saito TR, Suzuki M, Aoki-Komori S, Tanaka M. Food intake and leptin concentrations of lactating rats nursing various sized litters. Reprod Med Biol 2005; 4:203-206. [PMID: 29662392 DOI: 10.1111/j.1447-0578.2005.00106.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose: Leptin, the obesity (ob) gene product, has been proposed as an adipose-related satiety factor. It might act as a signal, from peripheral adipose stores to the central nervous system, to decrease food intake and increase energy expenditure. Conversely, low leptin concentrations after fasting or energy restriction might act to increase food intake. The present study investigated the role of the suckling stimulus in the mechanisms regulating body weight, food consumption and leptin concentration in lactating rats nursing different sized litters. Methods: The day of parturition was designated as day 0 of lactation. The rats were allocated randomly to three groups and the number of pups per litter was adjusted within one day of birth to eight (Group A), four (Group B) and two (Group C), with equal numbers of both sexes. From day 1 to day 10 of lactation, the separate weights of the mothers and pups, and the mothers' food intake were measured daily. On day 10, the rats were decapitated and blood was collected from the mothers for measurement of serum concentrations of leptin by ELISA. Results: Food intake by the mothers in Groups B and C decreased by about 20% and 30%, respectively, by day 10 of lactation, compared with Group A, but the serum leptin concentrations of those in Group C increased by about 80%, compared with Groups A and B. There was a high positive correlation between leptin concentration and fat pad weight. Conclusion: The findings suggest that the smaller litter in Group C reduced the energy cost of lactation, which induced an increase in the serum leptin concentration. (Reprod Med Biol 2005; 4: 203-206).
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Affiliation(s)
- Toru R Saito
- Behavioral Neuroscience Section, Graduate School of Veterinary Medicine
| | - Mitsuro Suzuki
- Behavioral Neuroscience Section, Graduate School of Veterinary Medicine
| | | | - Minoru Tanaka
- Division of Animal Physiology, Nippon Veterinary and Animal Science University, Musashino, Tokyo, Japan
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Shibata K, Hosoda H, Kojima M, Kangawa K, Makino Y, Makino I, Kawarabayashi T, Futagami K, Gomita Y. Regulation of ghrelin secretion during pregnancy and lactation in the rat: possible involvement of hypothalamus. Peptides 2004; 25:279-87. [PMID: 15063010 DOI: 10.1016/j.peptides.2004.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Accepted: 01/05/2004] [Indexed: 11/28/2022]
Abstract
We investigated the plasma concentration of ghrelin peptide during pregnancy and lactation in rats. Plasma ghrelin levels on days 10 and 15 of pregnancy were significantly lower than those of the non-pregnant rats. Thereafter, the plasma ghrelin levels on day 20 of pregnancy sharply increased to levels comparable with those in non-pregnant rats. Ghrelin peptide concentrations in the stomach did not change significantly during pregnancy. In the hypothalamus, ghrelin mRNA levels were significantly lower on day 15 of pregnancy than in the non-pregnant rats. Also, plasma ghrelin levels were significantly lower in lactating dams than non-lactating controls on days 3 and 8 of lactation. We examined the possible involvement of prolactin and oxytocin in the regulation of plasma ghrelin concentrations during lactation. Although plasma prolactin levels were decreased by the administration of bromocriptine, plasma ghrelin levels did not differ significantly between vehicle- and drug-treated lactating rats. Administration of haloperidol produced a marked increase in plasma prolactin levels as compared with the non-lactating controls. However, plasma ghrelin levels were not significantly different between vehicle- and drug-treated rats. Administration of an oxytocin antagonist into the lateral ventricle significantly inhibited the increase in the plasma oxytocin level induced by acute suckling. However, plasma ghrelin levels did not significantly between the groups. These observations indicated that the decrease in serum ghrelin is caused by a loss of the contribution of hypothalamic ghrelin. Furthermore, the present results suggested that the suckling stimulus itself, but the release of prolactin or oxytocin, is the factor most likely to be responsible for the suppression of ghrelin secretion during lactation.
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Affiliation(s)
- Kazuhiko Shibata
- Department of Hospital Pharmacy, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
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Sun G, Narita K, Murata T, Honda K, Higuchi T. Orexin-A immunoreactivity and prepro-orexin mRNA expression in hyperphagic rats induced by hypothalamic lesions and lactation. J Neuroendocrinol 2003; 15:51-60. [PMID: 12535169 DOI: 10.1046/j.1365-2826.2003.00862.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Orexins are endogenous neuropeptides that potently facilitate appetite and food consumption. In the present study, we examined orexin immunoreactivity and prepro-orexin mRNA expression in the lateral hypothalamus by immunohistochemistry and competitive reverse transcription-polymerase chain reaction (RT-PCR) methods in different models of hyperphagia in rats. Hyperphagia was induced by lesions of either the ventromedial hypothalamus (VMHL) or the paraventricular nucleus (PVNL), and we also compared lactating rats to nonlactating controls. Both VMHL and PVNL increased food intake and body weight compared to shams. On day 7 post lesion, serum leptin and insulin concentrations exhibited 3.2- and 2.8-fold increases in VMHL rats, and nonsignificant 1.8- and 1.8-fold increases in PVNL rats; there were significant decreases (48% and 33%) in lactating rats on day 12 postpartum compared to controls, respectively. Serum glucose concentrations were not significantly changed compared to controls in these rats. Quantification by image analysis suggests that VMHL significantly decreased the number and mean staining intensity of orexin-A immunoreactive neurones compared to those in the sham-lesioned group; while PVNL did not change orexin-A immunoreactivity. Competitive RT-PCR analysis showed that VMHL significantly decreased the prepro-orexin mRNA expression compared to those in the sham-lesioned group, and PVNL did not change it. Lactating rats on days 11-12 of lactation had significantly greater number and mean staining intensity of orexin-A immunoreactive neurones, prepro-orexin mRNA expression food intake and body weight than nonlactating postpartum rats. Thus, changes in orexin-A immunoreactivity and prepro-orexin mRNA expression were not consistent between the hyperphagia models. These results suggest that the hyperphagia from VMHL or PVNL and lactating rats differ in their involvement of orexin-A, and the change in circulating leptin and insulin concentrations may be involved in the change of orexin-A immunoreactivity in these rats.
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Affiliation(s)
- G Sun
- Department of Physiology, Fukui Medical University, Matsuoka, Fukui, Japan.
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Smith MS, Grove KL. Integration of the regulation of reproductive function and energy balance: lactation as a model. Front Neuroendocrinol 2002; 23:225-56. [PMID: 12127305 DOI: 10.1016/s0091-3022(02)00002-x] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Lactation is a physiological model for studying how the hypothalamus integrates peripheral signals, such as sensory signals (suckling stimulus) and those denoting energy balance (leptin), to alter hypothalamic function regulating food intake/energy balance and reproduction. The characteristics of food intake/energy balance during lactation are extreme hyperphagia, coupled with negative energy balance. The arcuate nucleus Neuropeptide Y (ARH-NPY) system is activated by: (1) brainstem projections specifically activated by the suckling stimulus, and (2) the decrease in leptin in response to the metabolic drain of milk production. NPY neurons from the ARH make direct contact with GnRH neurons and with CRH neurons in the PVH. NPY neurons also make contact with orexin and MCH neurons in the LHA, which, in turn, make contacts with GnRH neurons. Thus, the ARH-NPY system provides a neuroanatomical framework by which to integrate changes in food intake/energy with the regulation of cyclic reproductive function.
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Affiliation(s)
- M Susan Smith
- Division of Neuroscience, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
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12
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Stern JM, Keer SE. Acute hunger of rat pups elicits increased kyphotic nursing and shorter intervals between nursing bouts: implications for changes in nursing with time postpartum. J Comp Psychol 2002; 116:83-92. [PMID: 11926687 DOI: 10.1037/0735-7036.116.1.83] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Earlier findings, based on limited behavioral observations, indicate that nursing behavior in rats declines dramatically in duration over time postpartum-despite increasing ingestion of milk by rat pups to meet their growth and metabolic needs-although hungry pups elicit more nursing than do well-nourished pups. The authors compared the nursing pattern in detail for 6 hr on Days 7 and 14 and induced hunger in pups acutely with mammary-duct-ligated dams unable to provide milk. Compared with Day 7, on Day 14, supine nursing and the interval between nursing bouts increased, whereas hovering over pups and kyphotic nursing decreased. When pups were increasingly hungry, these age-related changes were counteracted. Thus, the ingestive motivation of pups largely regulates the nursing pattem over time.
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Affiliation(s)
- Judith M Stern
- Department of Psychology, Rutgers, The State University of New Jersey, Piscataway 08854-8020, USA.
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Speth RC, Barry WT, Smith MS, Grove KL. A comparison of brain angiotensin II receptors during lactation and diestrus of the estrous cycle in the rat. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:R904-9. [PMID: 10484510 DOI: 10.1152/ajpregu.1999.277.3.r904] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During lactation there are many dramatic alterations in the hypothalamic-pituitary (HP) axis, as well as an increased demand for food and water. The renin-angiotensin system (RAS) is one of the major mediators of the HP axis. This study examined the receptors for ANG II in the rat brain during lactation and diestrus. Compared with diestrus, lactating rats had significant decreases in ANG II receptor binding in several forebrain regions, most notably in the arcuate nucleus/median eminence, dorsomedial hypothalamic nucleus (DMH), and lateral hypothalamic area (LHA). In contrast, there was an increase in ANG II receptor binding in the preoptic area during lactation. These significant changes in ANG II binding in the brain during lactation support the hypothesis that changes in the RAS may contribute to the dramatic changes in the HP axis during lactation. In addition, the significant reduction in ANG II binding in the DMH and LHA may be indicative of a role in the regulation of food intake, a function only recently associated with the RAS.
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Affiliation(s)
- R C Speth
- Department of Veterinary Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman, Washington 99164, USA
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14
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Cook CJ. Maternal behaviour in sheep (Ovis aries) following administration of opioid agonists. N Z Vet J 1999; 47:67-70. [PMID: 16032073 DOI: 10.1080/00480169.1999.36113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AIMS As kappa(kappa)-opioids have marked effects on pain threshold in sheep during oestrus, late pregnancy and after birth, a study was undertaken to determine if kappa -opioids also had other roles during these states. METHODS Opioid agonists (GR89696, DAMAGO) were administered into either the lateral hypothalamus (LH) or amygdala of non-pregnant sheep (n = 5) or pregnant sheep (n = 15) in late pregnancy (n = 5) within 12 h of birth (n = 5) or in the third week after birth (n = 5). Cortisol, behavioural and electrocardiographic responses to an auditory stimulus were assessed with and without drug administration, as was feed consumption and suckling events. RESULTS In non-pregnant sheep, DAMAGO injected into either the LH or amygdala had little effect on the response to the auditory stimulus but when injected into the LH did decrease food consumption. GR 89696 had no obvious effects. In late pregnancy, cortisol and heart rate responses to the auditory stimulus were significantly reduced compared to the non-pregnant animals irrespective of treatment. This was also the case in the third week after birth. Immediately post-partum cortisol responses were closer to that seen in the non-pregnant animal. In late pregnancy and both post-partum periods, GR 89696 in the LH significantly increased feed consumption while DAMAGO had no significant effects. GR 89696 injected into the amygdala reduced the behavioural response to the auditory stimulus in late pregnancy and both post-partum periods. CONCLUSION Changes in sensitivity to opioids occur in both the amygdala and LH with pregnancy and after birth. These may influence maternal behaviours and feed intake.
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Affiliation(s)
- C J Cook
- Technology Development Group, Horticultural and Food Research Institute of New Zealand, Private Bag 3123, Hamilton, New Zealand
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15
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Olazabal DE, Ferreira A. Maternal behavior in rats with kainic acid-induced lesions of the hypothalamic paraventricular nucleus. Physiol Behav 1997; 61:779-84. [PMID: 9145952 DOI: 10.1016/s0031-9384(96)00567-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The rat maternal behavior consists of different pup-caring activities, such as retrieving, licking, and crouching. Mothers also build a nest, consume more food, are more aggressive, and show less fear behavior than in other stages of the reproductive cycle. It has been reported that oxytocin (OT) and the milk-ejection pathway could be involved in modulating maternal behavior. The paraventricular nucleus (PVN) of the hypothalamus forms part of the milk-ejection pathway and is also the major source of OT release in the brain. Kainic acid (KA) lesions (0.5 microg/0.5 microl) in the PVN performed on day 2 after parturition, affected retrieving behavior in the mother rat and produced a decrease in pups' weight gain. Because KA destroys only cell bodies, the changes that we observed could be due to the local destruction of neurons, rather than that of the fibers of passage. No alteration was observed in other components of the pup-caring activities, food intake, aggressive behavior, and fear in the lesioned mothers.
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Affiliation(s)
- D E Olazabal
- Departamento de Fisiología, Facultad de Veterinaria, Montevideo, Uruguay.
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Abstract
The present study was performed to investigate the effects of centrally administered oxytocin on weight gain and food intake in rats. Two substrains of Sprague-Dawley rats (A and B) differing in average daily weight gain were used. Female rats of substrain A gained 2 g per day and males gained 7 g. Female rats of substrain B gained 5 g per day and males gained 8 g. Animals were implanted with a stainless steel guide cannula, allowing ICV injections into the lateral ventricle. ICV injections of 1, 5, or 10 micrograms of oxytocin or isotonic saline in a volume of 5 microliters were given. In females, ICV treatment with either saline or 5 micrograms of oxytocin caused a transient loss of weight within 24 h of treatment. However, in the more slowly growing females of substrain A depression in body weight was observed after a single treatment with saline, whereas the body weight of oxytocin-treated females showed less marked depression and rapidly returned to the pretreatment weight. After a 3-day treatment period an even greater difference in daily weight gain was seen between oxytocin-treated and saline-treated female rats of substrain A. In contrast, no difference in daily weight gain or food intake was observed between oxytocin- and saline-treated male rats of substrain A, nor in females or males of the more rapidly growing substrain B. Intraperitoneal injections of 5 micrograms of oxytocin did not influence food intake or daily weight gain in female rats of substrain A. These data suggest that oxytocin may act centrally to influence food intake and daily weight gain in slowly growing female Sprague-Dawley rats.
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Affiliation(s)
- E Björkstrand
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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17
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Abstract
Young mammals come to approach the odor of their mother, a response that facilitates their survival during early life. Young rats induce a cascade of events in their mother to induce the emission of her odor. The pups increase circulating prolactin levels, which increases food intake and the emission of large quantities of cecotrophe containing the maternal odor. This odor is synthesized by the action of cecal microorganisms and changes with maternal diet. The diet-dependence of the odor requires the pups to acquire their attraction to the odor postnatally. The acquisition of this preference occurs when an odor is paired with the tactile stimulation that pups receive during maternal care. The action of the tactile stimulation appears to be mediated by noradrenaline. The development of this type of olfactory attraction is accompanied by changes in the regions of the olfactory bulb that are responsive to the attractive odor. Metabolic, anatomical, and neurophysiological changes in response to the attractive odor emerge in such regions of the bulb after early olfactory preference training.
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Affiliation(s)
- M Leon
- Department of Psychobiology, University of California, Irvine 92717
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18
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Abstract
1. Glomerular filtration rate (g.f.r.), renal plasma flow (r.p.f.), salt and water reabsorption and plasma concentrations of progresterone and prolactin were measured in virgins, 19 day pregnant and lactating rats. 2. G.f.r. was raised by about 40% in animals at 6-7 days of lactation when compared with virgins but towards the end of lactation returned to virgin levels. Salt and water reabsorption followed a similar pattern. 3. At the time of maximum change of g.f.r. during lactation r.p.f. was raised by about 30% and so filtration fraction rose by about 10% when compared with virgins. 4. Plasma prolactin and progesterone concentrations rose early in lactation but remained elevated when the renal changes had returned to normal. 5. Factors other than changes in prolactin and progesterone concentrations must be implicated in the changes in renal function that occur during lactation.
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Abstract
Lister hooded female rats, fed palatable high energy foods and chow, weighed significantly more than chow-fed control rats before mating. A smaller proportion of the obese rats became pregnant, and they lost more litters in lactation. When litters survived (7 +/- 1 pups), maternal weight changes differed between groups during lactation. The controls gained 6.2 +/- 3.2 g. whereas the obese rats lost variable amounts of weight despite the continued availability of the palatable diet. The rats that were heaviest at mating and parturition and which showed the largest non-fetal weight gains in pregnancy (i.e., the "large weight loss group") lost 60.6 +/- 4.8 g, while less obese rats which showed similar non-fetal gains to controls (i.e., the "small weight loss group") lost 24.6 3.2 g. Thus the weights of all groups converged and were similar after three weeks of lactation, but diverged again after weaning. During lactation the total energy intakes and amounts of protein consumed by the obese rats were significantly below those of controls, and total fat intake was significantly elevated. Although litter size and pup weights did not differ significantly at birth, pups of obese mothers weighed significantly less than those of controls at weaning. Maternal obesity in lactation appears to influence both body weight regulation and lactational performance.
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Tachi N, Tomogane H, Yokoyama A. Diurnal patterns of food intake and plasma corticosterone levels in lactating rats. Physiol Behav 1981; 27:481-6. [PMID: 7199736 DOI: 10.1016/0031-9384(81)90335-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Geiselman PJ, Martin JR, Vanderweele DA, Novin D. Dietary self-selection in cycling and neonatally ovariectomized rats. Appetite 1981; 2:87-101. [PMID: 7199893 DOI: 10.1016/s0195-6663(81)80002-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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22
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Pocius PA, Baumrucker CR, McNamara JP, Bauman DE. gamma-Glutamyl transpeptidase in rat mammary tissue. Activity during lactogenesis and regulation by prolactin. Biochem J 1980; 188:565-8. [PMID: 6104956 PMCID: PMC1161904 DOI: 10.1042/bj1880565] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The increased activity of gamma-glutamyl transpeptidase (EC 2.3.2.2) in rat mammary tissue at the onset of lactation was shown to involve prolactin. The timing and magnitude of these changes and its prolactin requirement suggest an important role in mammary function.
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23
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Weizenbaum F, Kenney NJ, Adler NT. Similarities in the regulatory patterns of pregnant and cycling rats. Physiol Behav 1979; 23:891-6. [PMID: 523545 DOI: 10.1016/0031-9384(79)90197-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The patterns of food intake, water intake and body weight of the female rat during the estrous cycle and pregnancy were determined. During the 4-day estrous cycle, intake and body weight were reduced on the day of ovulation. In contrast, animals with 5-day estrous cycles reduced intake and body weight for 2 days, the day prior to ovulation as well as on the day of ovulation. Intake of pregnant rats around the time of birth was compared to that of cycling females and similarities were observed. The peripartum pattern of food intake was systematically related to the length of the gestation period. Rats that littered 22 days after mating showed depressed food intake only on the day of birth. Those with 23-day gestation periods decreased food intake both on the day of birth and on the following day. The similarities in the intake patterns during 4- and 5-day estrous cycle to that of the peripartum segment of 22- and 23-day pregnancies suggest that there may be common neuroendocrine factors controlling these behaviors during the two reproductive periods.
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Gale SK, Van Itallie TB. Genetic obestiy: estrogenic influences on the body weight and food intake of lean and obese adult Zucker (fa/fa) rats. Physiol Behav 1979; 23:111-20. [PMID: 515200 DOI: 10.1016/0031-9384(79)90130-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The effects of chronic estrogen withdrawal and subsequent hormone replacement on the feeding and body weight of adult lean and genetically obese Zucker rats were investigated. Following confirmation of a delay in the vaginal canalization of the fatty rat, subgroups of each genotype received either ovariectomy or sham surgery (Experiment 1). One hundred days later all subjects were injected subcutaneously (SC) with 1.0 microgram of estradiol benzoate (EB) daily for 16 treatment days (Experiment 2A). A second series of daily 2.0 microgram EB injections was administered intraperitoneally (IP) for 1 week (Experiment 2B). The first experiment revealed that ovariectomy produced overeating and similar weight gains in both genotypes. In the second experiment, SC hormone treatment completely reversed ovarian obesity in lean animals but failed to alter the food intake or weight gain of fatty rats. IP administration of EB depressed the feeding of fatty and lean animals to a comparable degree but a reduction in weight gain was observed only in the lean rats. These findings are discussed in light of current theories of estrogenic modulation of energy balance.
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Fleming AS. Food intake and body weight regulation during the reproductive cycle of the golden hamster (Mesocricetus auratus). BEHAVIORAL BIOLOGY 1978; 24:291-306. [PMID: 743065 DOI: 10.1016/s0091-6773(79)90145-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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26
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Geiselman PJ, Almli CR. Effects of septal damage and ovariectomy on feeding, drinking and body weight. Brain Res Bull 1978; 3:457-66. [PMID: 122711 DOI: 10.1016/0361-9230(78)90075-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Septal destruction and ovariectomy each influenced food intake and body weight differentially. Animals sustaining septal damage ingested significantly more food than the other groups, and septal hyperphagia persisted for as long as 109 days. Ovarian hyperphagia did not occur under conditions of constant illumination. Septal destruction exerted essentially no effect on body weight, while ovariectomy substantially increased body weight. Sequential surgical manipulations provided further evidence that the ovaries and the septum influence food intake and body weight via independent mechanisms. Results indicated that the septal and ovarian effects on water intake are not mediated via independent mechanisms. Septal and ovarian hyperdipsia were found to be very robust effects occurring regardless of the lighting regimen. It was further demonstrated that ovarian hyperdipsia is not secondary to food intake but rather is primary hyperdipsia.
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Affiliation(s)
- P J Geiselman
- Department of Psychology, University of California, Los Angeles 90024
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27
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Croskerry PG, Smith GK, Leon M. Thermoregulation and the maternal behaviour of the rat. Nature 1978; 273:299-300. [PMID: 652033 DOI: 10.1038/273299a0] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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28
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Filial Responsiveness to Olfactory Cues in the Laboratory Rat. ADVANCES IN THE STUDY OF BEHAVIOR 1978. [DOI: 10.1016/s0065-3454(08)60133-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Abstract
In the following experiments, an attempt was made to determine the role of the ovary in the control of food intake and body weight regulation during lactation. In the first study, it was found that concentrations of estradiol benzoate effective in suppressing food intake and body weight in nonlactating animals were not effective during lactation. In the second experiment, ovariectomy during lactation was shown not to produce the usual increases in food intake and body weight or change in meal patterns known to occur after ovariectomy in the nonlactating rat. These results suggested that lactating animals behave the as though functionally ovariectomized and that the removal of the ovaries is of no additional consequence. The further observation that animals nursing small litters gained weight considerably more rapidly than animals nursing large litters led to the prediction that these animals would also be more responsive to the suppressive effects of EB. In the third study, EB in concentrations which are not effective in suppressing body weight in animals nursing large litters was found to suppress body weight in mothers with small litters. However, since these animals also showed a decline in milk yield, a number of alternative interpretations of these results were considered. These results, together with data concerning levels of ovarian hormones during gestation and lactation led to the hypothesis that pregnant and lactating animals undergo an elevation in body weight set-point, similar in magnitude and quality to elevations following ovariectomy in the nonlactating animal.
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Affiliation(s)
- A S Fleming
- Department of Psychology, University of California, Berkeley, USA
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32
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Abstract
The concentrations of nonesterified fatty acids and glycerol in rat parametrial adipose tissue increased at peak lactation. Adipose tissue from lactating rats showed higher rates of release of nonesterified fatty acids and glycerol when incubated in vitro than did tissue from nonlactating rats, but there was a substantial increase in the esterification of fatty acids during involution. These results support earlier evidence that fat reserves were mobilized during lactation.
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Wade GN. Sex Hormones, Regulatory Behaviors, and Body Weight. ADVANCES IN THE STUDY OF BEHAVIOR 1976. [DOI: 10.1016/s0065-3454(08)60085-6] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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35
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36
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37
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Ontogenetic and Phylogenetic Functions of the ParentOffspring Relationship in Mammals. ADVANCES IN THE STUDY OF BEHAVIOR 1971. [DOI: 10.1016/s0065-3454(08)60155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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38
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