Effects of steroid hormones on total brain Na(+)-k+ ATPase activity in Oreochromis mossambicus.
Indian J Exp Biol
;
2004 Mar; 42(3): 283-7
Article
in English
| IMSEAR
| ID: sea-57536
ABSTRACT
The effects of administration of cortisol, corticosterone, testosterone, progesterone and a synthetic estrogen. diethylstilbestrol (DES) on total brain Na(+)-K+- ATPase were investigated in tilapia, O. mossambicus. Exogenous administration of 0.125 and 0.25 microg/g body weight of glucocorticoids and 0.125, 0.25 and 0.5 microg/g body weight of DES for 5 days significantly stimulated Na+(-) K+ ATPase activity by 14-41% in the brain, while 0.5 microg/g body weight of glucocorticoids did not evoke any response on the activity of the enzyme. Progesterone (0.125 and 0.25 microg/g body weight) administration significantly decreased the enzyme activity by 21-36% and high dose (0.5 microg/g body weight) was ineffective. Testosterone exhibited a biphasic effect on Na(+)-K+ ATPase activity--a low dose stimulated by 14% while middle and high doses inhibited it by 19-24%. The results seem to be the first report on the effect of steroids on brain ATPase activity in a teleost. When 0.25microg/g body weight of actinomycin D or puromycin was administered prior to the treatment of similar doses of hormones, the inhibitors significantly inhibited the effect of the hormones by 24-52%. This clearly shows that the effect of the hormones was sensitive to the action of inhibitors suggesting a possible genomic mode of action under long-term treatment. The results suggest that cortisol, corticosterone and DES may possibly stimulate the co-transport of glucose and excitation of membrane potential while progesterone and testosterone inhibit them in the brain of O. mossambicus by regulating the activity of Na(+)-K+ ATPase.
Full text:
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Index:
IMSEAR (South-East Asia)
Main subject:
Progesterone
/
Steroids
/
Testosterone
/
Body Weight
/
Brain
/
Corticosterone
/
Hydrocortisone
/
Puromycin
/
Tilapia
/
Sodium-Potassium-Exchanging ATPase
Language:
English
Journal:
Indian J Exp Biol
Year:
2004
Type:
Article
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