Neonatal hypothyroidism alters the kinetic properties of Na+, K+-ATPase in synaptic plasma membranes from rat brain.
Neonatal hypothyroidism was induced in rat pups by injecting 131I within two days of birth and the effects on kinetic properties of Na+, K+-ATPase from synaptic plasma membranes were examined. Neonatal hypothyroidism resulted in a generalized decrease in V(max) with ATP, Na+, K+ and Mg2+ together with an increase in the K(m) for ATP, appearance of a low affinity component for Na+ and allosteric characteristic for the Mg2+-dependent activity at high Mg2+ concentrations. Binding pattern for Na+ and Mg2+ changed. Our results suggest that impairment of Na+, K+-ATPase activity together with altered kinetic properties could be one of the underlying biochemical mechanism leading to central nervous system (CNS) dysfunctions as a consequence of thyroid hormone deprivation during critical stages of brain development.
Billimoria
Framroze R
FR
Department of Biochemistry, Terna Medical College, Nerul, Navi Mumbai 400706, India.
Dave
Bharat N
BN
Katyare
Surendra S
SS
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation; D005260:Female; D007037:Hypothyroidism / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D007456:Iodine Isotopes / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013570:Synaptic Membranes / Q000201:enzymology*
D007456:Iodine Isotopes; D000254:Sodium-Potassium-Exchanging ATPase