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Abdoulaye Diané, Nikolina Nikolic, Alexander P Rudecki, Shannon M King, Drew J Bowie, and Sarah L Gray

third type of adipose cell, the brown in white (‘brite’) or ‘beige’ adipocyte. As in canonical BAT, the recruitment of brite adipocytes or ‘browning’ of WATs is induced by thermogenic stimuli such as cold as well as by pharmacological treatments such as

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Aldo Grefhorst, Johanna C van den Beukel, Wieneke Dijk, Jacobie Steenbergen, Gardi J Voortman, Selmar Leeuwenburgh, Theo J Visser, Sander Kersten, Edith C H Friesema, Axel P N Themmen, and Jenny A Visser

physiological way to activate BAT and induce ‘browning’ of WAT is by exposing animals to cold, resulting in an enhanced activity of the sympathetic nerves innervating BAT and WAT, thereby enhancing expression of proteins involved in thermogenesis and stimulating

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Patricia Joseph-Bravo, Lorraine Jaimes-Hoy, Rosa-María Uribe, and Jean-Louis Charli

). Energy demands activate the HPT axis Energy demanding situations such as hypothermia activate the thyroid ( Dempsey & Astwood 1943 , Brown-Grant et al . 1954 ). The cold response is blunted in pituitary-stalk operated rats ( Uotila 1939 ) and after PVN

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S C P Dutra, E G Moura, A L Rodrigues, P C Lisboa, I Bonomo, F P Toste, and M C F Passos

profound stimulatory effects on thermogenesis ( Bianco & Silva 1987 , Carvalho et al . 1991 , Silva 1995 , Gong et al . 1997 , Hausberg et al . 2002 , Ukropec et al . 2006 ). Cold exposure is associated with rapid activation of the hypothalamus

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Ladan Eshkevari, Eva Permaul, and Susan E Mulroney

major site for direct neuronal NPY and NE input to CRH cell bodies ( Suda et al . 1993 , Li et al . 2000 ). In several rodent models of chronic stress, such as cold stress, the increase in PVN NPY leads to stimulation of CRH synthesis and subsequent

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Raul Riquelme, Freddy Ruz, Artur Mayerhofer, and Hernán E Lara

and are associated with deregulation of ovarian function in pathologies such as polycystic ovary syndrome (PCOS). Exposure of adult rats to cold stress increases sympathetic activity and NA levels in the ovary ( Dorfman et al. 2003 , Bernuci et

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Elena Conte, Adele Romano, Michela De Bellis, Marialuisa de Ceglia, Maria Rosaria Carratù, Silvana Gaetani, Fatima Maqoud, Domenico Tricarico, and Claudia Camerino

). Oxt is also involved in thermoregulation which is essential in energy balance and in the etiology of obesity ( Trayhurn 2017 ). The lack of Oxtr leads to impaired thermogenesis with decreased core body temperature after acute exposure to cold

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V Squicciarini, R Riquelme, K Wilsterman, G E Bentley, and H E Lara

neuroendocrine control, in humans and rats, an increase in sympathetic nervous activity is related to the onset of PCOS ( Heider et al . 2001 , Sverrisdottir et al . 2008 ). The autonomic response to cold exposure increases the secretion of norepinephrine (NE

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Cintia B Ueta, Gustavo W Fernandes, Luciane P Capelo, Tatiane L Fonseca, Flávia D'Angelo Maculan, Cecilia H A Gouveia, Patrícia C Brum, Marcelo A Christoffolete, Marcelo S Aoki, Carmen L Lancellotti, Brian Kim, Antonio C Bianco, and Miriam O Ribeiro

) have increased susceptibility to cold-induced hypothermia as well as diet-induced obesity ( Bachman et al . 2002 , Jimenez et al . 2002 ). However, the relative contribution of each β adrenergic receptor isoform to these processes is less understood

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Cortisol pools were examined in six shorn sheep before (i.e. control conditions) and during their exposure to a cold, wet environment. Cortisol labelled with tritium was infused until equilibrium concentration [3H(eq)] was reached in the plasma; the infusion was then stopped and the instantaneous concentrations [3H(t)] determined at intervals during the next 20–40 min. A two-pool model was used to calculate results and the rate constants k 10, k 12 and k 21 were used to describe catabolism of hormone from the central pool, movement from the central to the outer pool and in the reverse direction respectively.

In the majority of cases when the fractional concentrations, [3H(t)]/-[3H(eq)], after infusion were plotted against time, curves representing control conditions indicated that the apparent rate of disappearance of cortisol from plasma was faster than from cold-stressed normothermic sheep. The apparent rate of disappearance of cortisol from the plasma of both control and cold-stressed normothermic sheep was faster than when the animals were hypothermic. These results were not obtained in two sheep when they were cold-stressed and normothermic and these are discussed.

The rate constants k 10, k 12 and k 21 obtained in the experiments bore the relation control < cold-stressed normothermic < hypothermic. The total amount of cortisol increased about 4 times, relative to control, when the sheep were cold-stressed and normothermic, and 40 times, relative to control, when they were hypothermic. Pools decreased in one cold-stressed normothermic sheep. Turnover rates were 7·7%, 7·0% and 3·7% of the total pool/min for sheep under control, cold-stressed normothermic and hypothermic conditions respectively.

It is concluded that the greatly increased plasma cortisol concentrations detected in cold-stressed normothermic and hypothermic sheep were associated with great increases in total cortisol, distributed in relatively constant 'spaces' in the body under those conditions.