The effects of environmental temperature on the hair coat of the mouse

Al-Hilli, F.; Wright, Eric A.

doi:10.1016/0306-4565(88)90005-8

Cited by 13 publications

(8 citation statements)

References 8 publications

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“….the tails of animals transferred from either hot to cold or cold to hot during their first 2 weeks after weaning immediately grew at the same rate as those of animals kept in these conditions continuously, thus indicating that heat was acting directly on bone growth" (Al-Hilli and Wright, 1983, p 34). In the same study, they also observed that tail vertebrae from warm-reared mice initially grew rapidly, and then matured faster and completed growth earlier than the mice at cooler temperatures (Al-Hilli and Wright, 1983). Consistent with these results, data here show that the warm mice had the lowest percent of tail growth during the maintenance phase (26% in the warm group compared to 36% in the cold and 30% in control), suggesting a faster rate of maturation.…”

Section: Evidence Of a Critical Period In Temperature Transfer Experisupporting

confidence: 87%

“…The temperatures were selected based on published literature (Sumner, 1909;Sundstroem, 1922;Ogle, 1934;Harrison et al, 1959;Barnett and Scott, 1963;Al-Hilli and Wright, 1983), and were confirmed to induce differential extremity growth in a pilot study. The cold and warm group cages were kept inside specially designed environmental chambers (Serrat Heating and Cooling, North Royalton, OH), and otherwise treated the same as controls.…”

Section: Materials and Methods Animals And Husbandrymentioning

confidence: 99%

“…Following methods described by Al-Hilli and Wright (1983), experiments were not started prior to weaning because: (1) individually caged mice do not survive temperature extremes at an earlier age, (2) mice kept with their mother and littermates still do not do well at temperature extremes as late as 12 days after birth, and (3) even when found to survive at an older age when kept with their mother and littermates, the high temperature of the nest prevents exposure to the intended experimental temperatures. Therefore, a consistent temperature-induced growth response cannot be elicited until the mice are housed alone after weaning (Al-Hilli and Wright, 1983).…”

Section: Treatment Agesmentioning

confidence: 99%

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Allen's Rule Revisited: Temperature Influences Bone Elongation During a Critical Period of Postnatal Development

Serrat

2013

The Anatomical Record

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Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of siblings housed in the cold. These highly reproducible lab results closely parallel the ecogeographical tenet described by Allen's extremity size rule, which states that appendage length correlates with temperature and latitude. It is unclear what mechanisms underlie these differences and in what pattern they emerge, since the morphology is traditionally thought to reflect naturally selected genomic adaptations for thermoregulation. This study tests the a posteriori hypothesis that adult extremity length is subject to substantial modification by temperature during a brief but critical period of early postnatal development. Weanling mice (N 5 28) were divided into three groups and housed at 7 C, 21 C, or 27 C for eight weeks. Tail lengths and body mass were measured weekly. Mass did not differ at any age. Analysis of tail elongation curves revealed two distinct phases: an initial period of rapid temperature-sensitive growth in which elongation rate was directly impacted by temperature; and a second phase of continued growth in which rates were identical among groups. Comparable growth reactions occur in response to other environmental variables such as exercise, suggesting that the skeleton is most responsive to external stimuli during a window of heightened sensitivity when growth occurs most rapidly. Knowledge of the timing and degree to which growth plasticity permits mammals to immediately adjust to novel temperature conditions will be important for analyzing skeletal variation in fluctuating climates, particularly for assessing factors that may accelerate skeletal evolution at temperature extremes. Anat Rec, 296:1534Rec, 296: -1545

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Section: Evidence Of a Critical Period In Temperature Transfer Experisupporting

confidence: 87%

Section: Materials and Methods Animals And Husbandrymentioning

confidence: 99%

Section: Treatment Agesmentioning

confidence: 99%

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Allen's Rule Revisited: Temperature Influences Bone Elongation During a Critical Period of Postnatal Development

Serrat

2013

The Anatomical Record

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“…Similarly, rats housed at 17°C from birth developed a greater coat mass than rats reared in the warm (54). In the above-mentioned studies, either the animals were exposed to cold shortly after birth or the parental generations had been living in the cold, but Al-Hilli and Wright (2) showed that even mice exposed to cold (8°C) at 23 days of age developed longer and thicker hair than control animals. However, even if such changes in fur should have occurred here in our experiments, we see no effects on insulation.…”

Section: Acclimation Temperature Does Not Affect Insulationmentioning

confidence: 99%

No insulating effect of obesity

Fischer

Csikasz

Essen

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

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The development of obesity may be aggravated if obesity itself insulates against heat loss and thus diminishes the amount of food burnt for body temperature control. This would be particularly important under normal laboratory conditions where mice experience a chronic cold stress (at Ϸ20°C). We used Scholander plots (energy expenditure plotted against ambient temperature) to examine the insulation (thermal conductance) of mice, defined as the inverse of the slope of the Scholander curve at subthermoneutral temperatures. We verified the method by demonstrating that shaved mice possessed only half the insulation of nonshaved mice. We examined a series of obesity models [mice fed high-fat diets and kept at different temperatures, classical diet-induced obese mice, ob/ob mice, and obesity-prone (C57BL/6) vs. obesityresistant (129S) mice]. We found that neither acclimation temperature nor any kind or degree of obesity affected the thermal insulation of the mice when analyzed at the whole mouse level or as energy expenditure per lean weight. Calculation per body weight erroneously implied increased insulation in obese mice. We conclude that, in contrast to what would be expected, obesity of any kind does not increase thermal insulation in mice, and therefore, it does not in itself aggravate the development of obesity. It may be discussed as to what degree of effect excess adipose tissue has on insulation in humans and especially whether significant metabolic effects are associated with insulation in humans. obesity; insulation; ob/ob DESPITE THE PRESENT INTEREST IN METABOLISM in connection with the global obesity epidemic, there is little knowledge concerning the extent to which obesity as such affects metabolism. There is widespread interest in issues such as the release of adipokines from adipose tissue depots, but many basic issues, such as the ability of adipose tissue to affect metabolism physically, have been little examined. One of these issues is the question of the ability of adipose tissue to function as a thermal insulation barrier, decreasing the heat loss from the organism and in this way decreasing the amount of energy needed to keep the organism warm, thereby increasing the amount of excess energy prone to storage in the form of (additional) fat.Whether an insulating effect of obesity exists is of significance both for humans and for animal models of obesity. However, with regard to experimental animals, the issue of insulation is of further interest. This is because most metabolic experiments are conducted with mice kept under conditions (standard laboratory conditions of Ϸ21°C) that are principally cold for the mouse (10,19,27,37,38,42,44) and thus where a high proportion of total metabolism (nearly half) is devoted to counteracting the resulting heat loss. This is a condition very different from that which is relevant for the metabolic physiology of most humans (living in a thermoneutral environment). Thus, under the current experimental conditions for mice, an insulating effect of increasing obesit...

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“…Shortened extremities minimize heat loss by reducing surface area relative to volume and have long been viewed as genetically determined thermoregulatory adaptations (1). However, the heritability of extremity length is largely unknown, because similar phenotypes can be reproduced in laboratory mammals by modifying their ambient rearing temperature (3)(4)(5)(6) (Fig. 1).…”

mentioning

confidence: 99%

Temperature regulates limb length in homeotherms by directly modulating cartilage growth

Serrat

King

Lovejoy

2008

Proc. Natl. Acad. Sci. U.S.A.

130

121

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Allen's Rule documents a century-old biological observation that strong positive correlations exist among latitude, ambient temperature, and limb length in mammals. Although genetic selection for thermoregulatory adaptation is frequently presumed to be the primary basis of this phenomenon, important but frequently overlooked research has shown that appendage outgrowth is also markedly influenced by environmental temperature. Alteration of limb blood flow via vasoconstriction/vasodilation is the current default hypothesis for this growth plasticity, but here we show that tissue perfusion does not fully account for differences in extremity elongation in mice. We show that peripheral tissue temperature closely reflects housing temperature in vivo, and we demonstrate that chondrocyte proliferation and extracellular matrix volume strongly correlate with tissue temperature in metatarsals cultured without vasculature in vitro. Taken together, these data suggest that vasomotor changes likely modulate extremity growth indirectly, via their effects on appendage temperature, rather than vascular nutrient delivery. When combined with classic evolutionary theory, especially genetic assimilation, these results provide a potentially comprehensive explanation of Allen's Rule, and may substantially impact our understanding of phenotypic variation in living and extinct mammals, including humans.Allen's Rule ͉ bone growth ͉ bone tissue culture ͉ cartilage biology ͉ thermoregulation E cogeographical rules relating climate to extremity length and body mass have long been central tenets of biology, and are among the best supported observations in natural-dwelling species (1). Allen's Rule codifies the observation that appendages (ears, limbs, and tails) of animals living in cold geographical regions are consistently shorter than those of closely related counterparts occupying warmer climes (2). Shortened extremities minimize heat loss by reducing surface area relative to volume and have long been viewed as genetically determined thermoregulatory adaptations (1). However, the heritability of extremity length is largely unknown, because similar phenotypes can be reproduced in laboratory mammals by modifying their ambient rearing temperature (3-6) (Fig. 1). The mechanism by which environmental temperature modulates extremity growth has remained elusive (7,8). Understanding growth plasticity is critical to basic evolutionary analyses, because many characters that have long been hypothesized to be adaptations may instead be partial or even entirely effects of ambient temperature (9, 10). Moreover, knowledge of this phenotypic plasticity will be a key factor in ecological conservation strategies for anticipated changes in global climate that may have direct impacts on human economics and sustainability (11).The traditional explanation for temperature-growth effects in skeletal extremities is an altered supply of essential nutrients and growth factors via increased or decreased blood flow that results from changes in vasomotor tone (i.e., t...

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The effects of environmental temperature on the hair coat of the mouse

Cited by 13 publications

References 8 publications

Allen's Rule Revisited: Temperature Influences Bone Elongation During a Critical Period of Postnatal Development

Allen's Rule Revisited: Temperature Influences Bone Elongation During a Critical Period of Postnatal Development

No insulating effect of obesity

Temperature regulates limb length in homeotherms by directly modulating cartilage growth

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