title: A sensitive solid phase enzymeimmunoassay for norethisterone (norethindrone) in saliva and plasma.
abstract: A sensitive, solid phase enzymeimmunoassay suitable for determining norethisterone in small aliquots of plasma (10 microliters) and saliva (100 microliters) has been developed. A solid phase antiserum raised against a norethisterone-11 alpha-hemisuccinyl/bovine serum albumin conjugate was prepared by coupling to cyanogen bromide activated cellulose. A norethisterone/horseradish peroxidase conjugate was used as enzyme label, o-phenylenediamine/hydrogen peroxide being the substrate for colour development. The assay had a lower limit of sensitivity of 3 pg/assay tube and satisfied accepted validation criteria. Norethisterone concentrations determined by enzymeimmunoassay and by a well established radioimmunoassay were in excellent agreement in both plasma (r = 0.993, n = 20) and saliva (r = 0.989, n = 15). Plasma and salivary norethisterone concentrations determined in healthy volunteers reached peak values at about 1 hour after administering a norethisterone-containing oral contraceptive preparation. The maximum values achieved in saliva (775--1430 pmol/l) were only approximately 3% of those observed in plama. Since salivary norethisterone concentrations reflected those in plasma, they may be useful in fertility control programmes and pharmacokinetic studies.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002214:Capsules; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D009640:Norethindrone / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D011863:Radioimmunoassay; D012463:Saliva / Q000032:analysis*; D013607:Tablets
chemical_list: D002214:Capsules; D013607:Tablets; D009640:Norethindrone