Induction of thyroid hormone in changing Na+K(+)-ATPase activity in different organs of toad, Bufo melanostictus.
Single injection of T3, at the doses of 0.5 and 1 micrograms/g body weight, stimulated Na+K(+)-ATPase activity of crude liver homogenate of toad in a dose dependent fashion. Lowering the dose of T3 to 0.25 micrograms/g had no effect on the enzyme activity. T3 at the dose of 2 micrograms/g showed the same level of enzyme activity at par with that of 1 microgram/g. Na+K(+)-ATPase activity of muscle increased with T3 at the doses of 1 and 2 micrograms/g, but without any dose dependent manner while T3 at the doses of 0.25 and 0.5 micrograms/g remained unresponsive in changing the enzyme activity. T4, after 3 consecutive injections, increased the enzyme activity in liver with 1 and 2 micrograms/g and in muscle with 2 micrograms/g only while the other doses of T4 (0.25 and 0.5 micrograms/g in case of liver and 0.25, 0.5, and 1 micrograms/g in case of muscle) had no effect on the enzyme activity. Brain showed no alteration to Na+K(+)-ATPase activity with the same doses of T3 and T4. Cycloheximide counteracted the T3 induced rise in enzyme activity. The reduced level of Na+K(+)-ATPase activity in the PTU treated toad was recovered and brought to the control level after 3 consecutive injections of T4 at the dose of 1 microgram/g.
Dey
S S
SS
Department of Animal Physiology, Bose Institute, Calcutta India.
D000818:Animals; D001921:Brain / Q000201:enzymology; D002025:Bufonidae / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D008099:Liver / Q000201:enzymology*; D009132:Muscles / Q000201:enzymology*; D011441:Propylthiouracil / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013963:Thyroid Hormones / Q000494:pharmacology*; D013974:Thyroxine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014284:Triiodothyronine / Q000037:antagonists & inhibitors / Q000494:pharmacology
D013963:Thyroid Hormones; D014284:Triiodothyronine; D011441:Propylthiouracil; D003513:Cycloheximide; D000254:Sodium-Potassium-Exchanging ATPase; D013974:Thyroxine