Tissue distribution of high-density lipoprotein labeled with radioiodinated cholesterol.
This preliminary study was undertaken in order to explore possible methods for enhancing the target organ specificity of radioiodinated cholesterol. 19-[125I]cholesterol (IC) was rapidly incorporated and transported in high-density lipoproteins (HDL) following i.v. admnistration to rats, and thus behaved like cholesterol in this regard. Incorporation of IC into HDL (IC-HDL) before administration produced little change in the tissue distribution profile except for a reduction in the amount of radioactivity appearing in the thyroid. This suggested that the lipoprotein carrier may have afforded protection from metabolic dehalogenation of IC. When rats were pretreated with 4-aminopyrazolo-(3,4d)-pyrimidine to drastically reduce the circulating lipoprotein levels, a fourfold enhancement in adrenal uptake was observed following administration of IC-HDL. This finding was consistent with the current view that the rat adrenal contains high-affinity and saturable receptors for HDL.
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D005260:Female; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008075:Lipoproteins, HDL / Q000378:metabolism*; D051381:Rats; D013961:Thyroid Gland / Q000378:metabolism; D014018:Tissue Distribution
D007457:Iodine Radioisotopes; D008075:Lipoproteins, HDL; C004420:4-aminopyrazolo(3,4-d)pyrimidine; D002784:Cholesterol; D000225:Adenine