Exposure to artificial wind increases energy intake and reproductive performance of female Swiss mice (<i>Mus musculus</i>) under hot temperature

Deng, Guang-Min; Yu, Jing-Xin; Bao, Yu-Fan; Chen, Qian; Cao, Jing; Zhao, Zhanzheng

doi:10.1242/jeb.231415

Cited by 3 publications

(1 citation statement)

References 51 publications

(66 reference statements)

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“…This was followed by consideration that lactation performance was limited by capacity of the mammary gland to produce milk (Hammond et al 1994(Hammond et al , 1996Yang et al 2013;Zhao et al 2013;Wen et al 2017). Finally, the concept of a heat dissipation limit (HDL) associated with the capacity of lactating females to get rid of body heat generated as a by-product of processing food and producing milk was developed (Król and Speakman 2003a, b;Król et al 2003Król et al , 2007Król et al , 2011Speakman and Król 2010a, b;Sadowska et al 2016;Deng et al 2020;Huang et al 2020a;Ohrnberger et al 2020;Zhao et al 2020b). Lactogenic heat production in laboratory mice is sufficiently high to double their daily energy expenditure at peak lactation (Król and Speakman 2019), leading to the sustainably elevated maternal body temperature (Gamo et al 2013), a phenomenon reported in several species of lactating rodents and in large domestic animals (Speakman 2008;Hansen 2009).…”

Section: Introductionmentioning

confidence: 99%

Fur removal promotes an earlier expression of involution-related genes in mammary gland of lactating mice

et al. 2023

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Peak lactation occurs when milk production is at its highest. The factors limiting peak lactation performance have been subject of intense debate. Milk production at peak lactation appears limited by the capacity of lactating females to dissipate body heat generated as a by-product of processing food and producing milk. As a result, manipulations that enhance capacity to dissipate body heat (such as fur removal) increase peak milk production. We investigated the potential correlates of shaving-induced increases in peak milk production in laboratory mice. By transcriptomic profiling of the mammary gland, we searched for the mechanisms underlying experimentally increased milk production and its consequences for mother–young conflict over weaning, manifested by advanced or delayed involution of mammary gland. We demonstrated that shaving-induced increases in milk production were paradoxically linked to reduced expression of some milk synthesis-related genes. Moreover, the mammary glands of shaved mice had a gene expression profile indicative of earlier involution relative to unshaved mice. Once provided with enhanced capacity to dissipate body heat, shaved mice were likely to rear their young to independence faster than unshaved mothers.

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Section: Introductionmentioning

confidence: 99%

Fur removal promotes an earlier expression of involution-related genes in mammary gland of lactating mice

et al. 2023

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The nonshivering thermogenesis of brown adipose tissue and fat mobilization of striped hamsters exposed to cycles of cold and warm temperatures

Huo

Bao

Cao

et al. 2022

The European Zoological Journal

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Limits to sustained energy intake. XXXIII. Thyroid hormones play important roles in milk production but do not define the heat dissipation limit in Swiss mice

Yang,

Cao,

Speakman

et al. 2023

Journal of Experimental Biology

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The limits to sustained energy intake set physiological upper boundaries that affect many aspects of human and animal performance. The mechanisms underlying these limits however remain unclear. We exposed Swiss mice to either supplementary thyroid hormones (THs) or methimazole during lactation at 21 °C or 32.5 °C, and measured food intake, resting metabolic rate (RMR), milk energy output (MEO), serum THs and mammary gland gene expression of females, and litter size and mass of their offspring. Lactating females developed hyperthyroidism following exposure to supplementary THs at 21 °C, but they did not significantly change body temperature, asymptotic food intake, RMR or MEO, and litter and mass were unaffected. Hypothyroidism, induced by either methimazole or 32.5 °C exposure, significantly decreased asymptotic food intake, RMR and MEO, resulting in significantly decreased litter size and litter mass. Furthermore, gene expression of key genes in the mammary gland were significantly decreased by either methimazole or hot exposure, including gene expression of THs and prolactin receptors, and Stat5a and Stat5b. This suggests that endogenous THs are necessary to maintain sustained energy intake and milk energy output. Suppression of the thyroid axis seems to be an essential aspect of the mechanism by which mice at 32.5 °C reduce their lactation performance to avoid overheating. However, THs do not define the upper limit to sustained energy intake and milk energy output at peak lactation at 21 °C. Another, as yet unknown, factor, prevents supplementary thyroxine exerting any stimulatory metabolic impacts on lactating mice at 21 °C.

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Exposure to artificial wind increases energy intake and reproductive performance of female Swiss mice (Mus musculus) under hot temperature

Cited by 3 publications

References 51 publications

Fur removal promotes an earlier expression of involution-related genes in mammary gland of lactating mice

Fur removal promotes an earlier expression of involution-related genes in mammary gland of lactating mice

The nonshivering thermogenesis of brown adipose tissue and fat mobilization of striped hamsters exposed to cycles of cold and warm temperatures

Limits to sustained energy intake. XXXIII. Thyroid hormones play important roles in milk production but do not define the heat dissipation limit in Swiss mice

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