The influence of lithium on biokinetics and biodistribution of 65Zn under different dietary protein regimens in rats.
The present study was designed to evaluate the effect of lithium on the biological half-lives of 65Zn in the rat liver and whole body and also its biodistribution under different dietary protein regimens. To carry out these investigations, each rat after three weeks of different treatments was injected with 1.85 MBq of 65Zn, intraperitoneally (ip) and its radioactivity was recorded in liver as well as in whole body by using gamma ray spectrometer. The radionuclide 65Zn showed two kinetic components indicating its biological half-life: Tb1 the initial fast component and the Tb2 or slow component. Protein deficiency led to a significant elevation of both components in the whole body but not in the liver when compared to the control group. High protein (HP) diet in rats resulted in marked reduction in both components in the liver but not in the whole body. Lithium treatment alone to normal rats caused a significant reduction in the Tb2 but not in the Tb1 component in the whole body as well as in the liver. The administration of lithium normalized the observed increase in both components in the whole body of protein deficient rats. On the contrary, in rats fed with low protein (LP) diet after lithium treatment the Tb(2) component was significantly reduced in the liver. Lithium treatment to HP fed rats, showed a significant decrease in both components in the liver when compared to normal rats: however this decrease was less pronounced in comparison to the HP group that had not been given lithium. Furthermore, one day prior to the end of the treatment period, the rats were injected ip with a tracer dose of 0.37 MBq 65Zn and 24 h later, various organs were excised for 65Zn biodistribution measurements in vitro. Under different dietary protein regimens as well as after administration of lithium the percent uptake values of 65Zn varied in various organs viz: the brain, liver, kidney, small intestine and large intestine as well as in the blood. In conclusion, different protein dietary conditions on co-administration with lithium in the rats seemed to have a dominant role for the retention of 65Zn in the liver the whole body and in other organs.
Tandon
Aparna
A
Department of Biophysics, Panjab University, Chandigarh-160014, India.
Dani
Vijayta
V
Nagpaul
Joginder
J
Dhawan
Devinder
D
D000284:Administration, Oral; D000818:Animals; D018753:Diet, Protein-Restricted / Q000379:methods*; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D006207:Half-Life; D008094:Lithium / Q000008:administration & dosage*; D008099:Liver / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D014915:Whole-Body Counting; D015037:Zinc Radioisotopes / Q000493:pharmacokinetics*
D004044:Dietary Proteins; D019275:Radiopharmaceuticals; D015037:Zinc Radioisotopes; D008094:Lithium