Age-related differences in the response of hepatic oxygen consumption to thermal stress in the male garden lizard.

Autor: Kara TC, Patnaik BK
Jazyk: angličtina
Zdroj: Archives of gerontology and geriatrics [Arch Gerontol Geriatr] 1985 Apr; Vol. 4 (1), pp. 29-35.
DOI: 10.1016/0167-4943(85)90015-9
Abstrakt: The main aim of the present study is to compare the thermal adaptation capacity of young, middle-aged and old lizards with respect to hepatic oxygen consumption. Cold exposure (1 h at 0-4 degrees C) caused a decline in endogenous oxygen consumption in young but did not evoke significant changes in middle-aged and old lizards. On the other hand, with 5 mM succinate the rate of respiration increased marginally only in cold-exposed old lizards. This suggests that the metabolic response to cold is age-dependent in these lizards. Exposure of homogenates at 40 +/- 1 degree C for 15 min led to a rise in the hepatic oxygen consumption of young but not in that of either middle-aged or old lizards. There were no changes in the rate of oxygen consumption upon exposure for a similar period at 45 +/- 1 degree C of liver homogenates from lizards of three different age groups. However, exposure at 51 +/- 1 degree C resulted in a higher degree of decline in the rate of hepatic oxygen consumption in middle-aged and old than in young lizards. Thus, the young lizards appear to be better-adapted to hyperthermic stress than the middle-aged and old.
Databáze: MEDLINE