Isocitrate dehydrogenase activity and its regulation by estradiol in tissues of rats of various ages.
The activity and hormonal regulation of NAD- and NADP-linked isocitrate dehydrogenase (EC.1.1.1.41 and EC.1.1.1.42, respectively) in the brain, liver and kidney cortex of female rats of various ages was investigated. The activity of NAD-ICDH of brain was greater than extramitochondrial (-c) or intramitochondrial (-m) NADP-ICDH. In contrast, liver c-NADP-ICDH was much higher than NAD- or m-NADP-ICDH, whereas in kidney cortex the activity of m-NADP-ICDH is dominant over both NAD- and c-NADP-ICDH in all the age group of rats studied. The activity of the NAD-ICDH of brain and all the enzymes of liver and kidney cortex increases until adulthood (33-weeks) and decreases thereafter in old rats (85-weeks). In brain c-NADP-ICDH was much higher in immature (6-weeks) rats and decreases with increasing age of the animal, whereas m-NADP-ICDH showed no significant change with the age of the rats. Bilateral ovariectomy decreases the level of all the three forms of enzyme in all the tissues of 6-, 13- and 33-week rats but failed to show any significant effect in 85-week old rats. Exogenous administration of estradiol induces all the three forms of enzyme in all the tissues of ovariectomized rats. The degree of response is tissue- and age-specific.
Yadav
R N
RN
Department of Life Sciences, Dibrugarh University, Assam, India.
D000375:Aging; D000818:Animals; D001921:Brain / Q000201:enzymology; D004958:Estradiol / Q000502:physiology*; D005260:Female; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D007672:Kidney Cortex / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010052:Ovariectomy; D051381:Rats
D009243:NAD; D004958:Estradiol; D009249:NADP; D007521:Isocitrate Dehydrogenase