Changes in the hypothalamo-pituitary-adrenocortical and hypothalamo-pituitary-thyroid axes in diabetic rats acclimated to moderate hyperthermic environment

Dinevska-Ќovkarovska, Suzana; Guladin, Teuta; Miova, Biljana; Mitev, Slavco; Gerazova, Katerina

doi:10.1016/j.jtherbio.2009.02.001

Cited by 3 publications

(5 citation statements)

References 18 publications

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“…Besides the well-known hepatic glycogenolysis in the STHA [6][7][8], we also observed intensive glycogenolysis at the level of heart Glk stores (Fig. 1).…”

Section: Short-term Heat Acclimationsupporting

confidence: 63%

“…Several other investigations suggest that the acclimation-induced augmentation of constitutive Glk is accompanied by parallel enzymatic changes which may affect the rate of glycogenolysis [11]. Some of these metabolic features, characteristic of the heart during heat acclimation are due to a sustained low thyroxin level [3,6,8,11,[26][27][28]. Several other investigations have reported that hypothyroidism is also associated with a dramatic loss in the activity of heart PFK-1, as well as PFK-2 activity and fructose 2,6 bisphosphate level [29][30][31].…”

Section: Long-term Heat Acclimationmentioning

confidence: 98%

“…In this sense, there is an enhancement of the metabolic machinery to elevate the energy potential of heat-acclimated organism which is accompanied by a decrease of the rate of the whole body metabolism [4,5]. Metabolic changes which are most evident during heat acclimation are: energy sparing, which is manifested as a rebound of liver glycogen (Glk) in rats [6][7][8] and hamsters [9] (as a result of increased activity of enzymes involved in a direct Glk synthesis), and decreased glucose (Glu) production [6][7][8]. As is the case with the liver, heat acclimation produces favorable adaptations in mechanical and metabolic aspects of the heart performance, such as: twofold greater heart Glk level, increased b-adrenergic sensibility, lowered heart rate and greater stroke volume.…”

Section: Introductionmentioning

confidence: 99%

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Heat acclimation-induced changes in heart glycogen/glucose metabolism in rats

et al. 2011

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Based on the observation that heat acclimation is a slowly developing response, evoked by continuous exposure to moderate heat, we investigated the time-dependent acclimatory changes of heart glycogen metabolism. Cardiac levels of key carbohydrate-related enzymes and substrates were studied in the function of the duration of short-term (STHA; 6, 12, 24 and 48 h) and long-term heat acclimation (LTHA; 7, 14, 21 and 30 days) to high environmental temperature (35 ± 1°C). The changes in heart glycogen metabolism during STHA could be separated in two phases: up to 12 h exposure, where significant decrease of the heart glycogen (Glk), glucose-6-phosphate (G6P), hexokinase (HK) activity as well as increase of heart glucose was observed; and from 24 to 48 h exposure, manifested with elevation of Glk, Glu, glycogen phosphorylase a (GPa), phosphofructokinase (PFK) and HK activities. The metabolic changes in the period of LTHA could also be seen as separate phases: in a period of 7-14 days of heat exposure there was an increase of heart Glk, Glu, G6P, HK, as well as a decrease of GPa and PFK, while in the period of 21-28 days there was more intensive rebound of Glk and G6P, increase of GPa activity and non-significant changes of Glu, HK and PFK. The results obtained have showed that acclimation to moderate hyperthermic environment has caused significant changes in examined parameters which differ depending on duration to the exposure: intensive stress-induced glycogenolytic and glycolytic processes in the period of STHA and intensive energy sparing, manifested by Glk deposition in the period of LTHA.

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“…Besides the well-known hepatic glycogenolysis in the STHA [6][7][8], we also observed intensive glycogenolysis at the level of heart Glk stores (Fig. 1).…”

Section: Short-term Heat Acclimationsupporting

confidence: 63%

Section: Long-term Heat Acclimationmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Heat acclimation-induced changes in heart glycogen/glucose metabolism in rats

et al. 2011

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“…Long-term heat-acclimated animals. Heat acclimation was attained by continuous exposure to 3571 1C and 30-40% relative humidity for 28 days (long-term heat acclimation LTHA) as previously described (Mitev et al, 2005;Dinevska-Chovkarovska, 1998;Miova et al, 2008;Dinevska-Kjovkarovska et al, 2009;Chayoth and Cassuto, 1971;Horowitz, 1976;Eynan et al, 2002;Maloyan et al, 1999), in an air-flowed heat chamber (4.20 m Â 2.0 m Â 3.0 m).…”

Section: Experimental Animals and Designmentioning

confidence: 99%

“…The animals from each thermal group were divided into three subgroups, as previously designed by Dinevska-Kjovkarovska et al (2009): 1. Control animals (C, C 1 ); 2.…”

Section: Experimental Animals and Designmentioning

confidence: 99%