**5.4 Low density lipoprotein (LDL) receptors**

Plasma lipoprotein transports cholesterol towards adrenal gland that act as the substrate for synthesis of steroid hormone. **131I-iodomethyl-norcholeterol** 

**(NP 59)** used to identify patients suffering from adrenal cortex. Cholesterol analogs, **131I-iodocholestrol and 75Se-iodomethyl-norcholestrol,** are under investigation for clinical advantages to detect malignant tissues. Besides N59, various iodine labeled hormonal products are undergo transportation and localization with the help of LDL receptors. A corticosteroid, Dexamethasone, reduce cholesterol uptake by controlling the production of ACTH [74].
