Influence of long-term exposure to adverse environments on organ weights and histology

Hale, Henry B.; Mefferd, Roy B.; Vawter, Gordon F.; Foerster, G. Elizabeth; Criscuolo, Dominic

doi:10.1152/ajplegacy.1959.196.3.520

Cited by 28 publications

(8 citation statements)

References 2 publications

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“…35, No. 6, 1985 to previously reported results (HALE et al, 1959;TUCKER and HORVATH, 1973). An increased relative adrenal weight has been accepted as a good measure of the level of stress.…”

Section: Discussionsupporting

confidence: 80%

Enzymatic responses and adaptations to swimming training and hypobaric hypoxia in postnatal rats.

1985

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Twenty four male Sprague-Dawley rats, 35 days old, were randomly assigned to one of four groups : 2 resting control groups and 2 swimming groups. The sea level-control and the sea level-swimming groups were housed 5 weeks at 1,011 hPa (760 mmHg) while the hypoxic control and swimming groups were housed for 1 week at 678 hPa, followed by 4 weeks at 611 hPa. The swimming rats were subjected to a swimming program of 30 min, 6 days/week for 5 weeks. Both hypoxia groups developed significantly higher Hb and Hct levels than the sea level groups. The glycogen content in the extensor digitorum longus (EDL) and the deep portion of the vastus lateralis (DVL) muscles of the sea levelswimming group were significantly greater as compared to the hypoxia swimming group. The succinate dehydrogenase (SDH) activity in the sea level-control group was significantly lower in the EDL muscle than in the 3 other groups, and in the DVL muscle lower than that of the sea levelswimming group. Histochemically, hypoxia and swimming training induced significant increases in the fast-twitch-oxidative-glycolytic (FOG) fibers (6-11 %) in soleus muscle, and decreases in the slow-twitch-oxidative (SO) fibers. The EDL muscles had significantly higher percentages of FOG fibers in the hypoxia and swimming groups than in the sea level control group. On the basis of the present study it seems probable that hypoxia is a triggering factor for the conversions of muscle fiber types and the increase in oxidative capacity.

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Section: Discussionsupporting

confidence: 80%

Enzymatic responses and adaptations to swimming training and hypobaric hypoxia in postnatal rats.

1985

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“…Consonant with earlier observations, increased relative hepatic weight was noted in the presence of growth retardation after cold adaptation (17). The increased relative liver weight was associated with an enlarged hepatic space of T4 and, to a lesser degree, of Ta.…”

Section: Methodssupporting

confidence: 78%

Augmentation of the Peripheral Metabolism of l-Triiodothyronine and l-Thyroxine after Acclimation to Cold

Balsam¹,

Leppo²

1974

J. Clin. Invest.

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A B S T R A C T Increased metabolism of thyroid hormones was observed in rats adapted to an ambient temperature of 4°C. The increased hormonal degradation was manifested in enhanced metabolic, urinary deiodinative, biliary, and fecal clearances of iodothyronines. Increased metabolic clearances were due to stimulation of cellular hormonal disposition, evidenced by elevated intrinsic cellular clearances. After adaptation, the concentration of protein-bound iodine in plasma was decreased, and the binding of the hormones by plasma proteins was increased. The enhanced rate of metabolism of iodothyronines was associated with stimulation of the binding of these hormones by diverse tissues, suggesting the participation of extrahepatic degradative foci in the increased hormonal deiodination observed in vivo. Increased hepatocellular binding and a significantly enlarged hepatic distribution space of thyroxine were noted. Hepatocellular binding of triiodothyronine was similarly augmented, and a smaller but signiificant increase in the hepatic space of this iodothyronine was detected. Analysis of the hepatic subcellular partition of iodothyronines 35 min after the intravenous administra-

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“…The effects of cafeteria feeding and chronic cold exposure on body, heart, and IBAT weights are shown in Table II. Cold-exposed animals gained less weight than either of the other two groups, but hypertrophy of both heart and IBAT occurred as described (1,5,25,26). Cafeteria feeding did not lead to greater weight gain than that seen in control animals, a consistent finding in rats of this age, but did stimulate IBAT growth (4).…”

Section: Pharmacologicalsupporting

confidence: 56%

Effect of Diet and Cold Exposure on Norepinephrine Turnover in Brown Adipose Tissue of the Rat

Young¹,

Saville²,

Rothwell³

et al. 1982

J. Clin. Invest.

336

153

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A B S T R A C T Brown adipose tissue (BAT)is an important site of adaptive changes in thermogenesis in the rat. The sympathetic nervous system, which richly supplies BAT, is thought to play an important role in the regulation of BAT thermogenesis because catecholamines stimulate and beta adrenergic blocking agents inhibit oxygen consumption in this tissue. The present studies were carried out to assess directly sympathetic activity in BAT in response to cold exposure and to changes in dietary intake, both of which alter heat production in the rat. Sympathetic activity was determined from the rate of norepinephrine (NE) turnover in interscapular brown adipose tissue (IBAT) after preliminary experiments validated the use of NE turnover techniques in IBAT. Acute exposure to 4°C increased NE turnover in IBAT 4-to 12-fold compared with ambient temperature controls, depending upon the interval over which the turnover measurement was made, while in the heart NE turnover doubled in response to the same cold stimulus. In animals exposed to cold continuously for 10 d before study, NE turnover measurements in IBAT and in the heart were elevated comparably to those obtained during acute exposure. Alterations in feeding were also associated with changes in NE turnover in IBAT. Fasting for 2 d decreased NE turnover in IBAT (-35% from 29.2±4.2 ng NE/h to 18.9±5.9) and in heart (-52%). In animals fed a "cafeteria" diet, a model of voluntary overfeeding in the rat, NE turnover was increased in both IBAT (+108% from 24.8±4.5 ng NE/h to 51.7±6.8) and heart (+66%). Because ganglionic blockade exerted a greater effect on NE turnover in IBAT in cafeteriafed rats than in controls, the increase in NE turnover in IBAT with this overfeeding regimen reflects enhanced central sympathetic outflow. Thus NE turnover techniques can be satisfactorily applied to the

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Influence of long-term exposure to adverse environments on organ weights and histology

Cited by 28 publications

References 2 publications

Enzymatic responses and adaptations to swimming training and hypobaric hypoxia in postnatal rats.

Enzymatic responses and adaptations to swimming training and hypobaric hypoxia in postnatal rats.

Augmentation of the Peripheral Metabolism of l-Triiodothyronine and l-Thyroxine after Acclimation to Cold

Effect of Diet and Cold Exposure on Norepinephrine Turnover in Brown Adipose Tissue of the Rat

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