title: A novel, nonradioactive in vivo bioassay of thyrotropin (TSH).
abstract: A new and simple in vivo bioassay suitable for routine testing of pituitary and recombinant TSH preparations was developed. Male Albino Swiss CF-1 mice were given T3 in their drinking water to suppress endogenous TSH. T3, 3.0 micrograms/mL, given to mice for a period of 4 days decreased plasma total T4 (TT4) level to less than 10% of the nonsuppressed (control) level. Various doses of exogenous pituitary and recombinant TSH preparations were injected intraperitoneally and blood samples were obtained from the orbital sinus 6 h later. The TT4 level, measured by radioimmunoassay, served as the assay end-point. The assay required injection of approximately 3.0 micrograms of pituitary human TSH (phTSH), 1.0 microgram recombinant human TSH (rhTSH), 0.2 microgram bovine TSH (bTSH), and 0.1 microgram rat TSH (rTSH) to attain half-maximal response. The maximal level of TT4 after TSH stimulation was similar to that observed in normal, nonsuppressed mice. The procedure developed is relatively easy to perform, economical, and, unlike earlier TSH bioassays, does not require the use of radionuclides. This bioassay showed acceptable sensitivity and reliability in structure-function studies of pituitary TSH from different species as well as rhTSH.
authors.affiliation: Molecular and Cellular Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: J
authors.initials: J
authors.lastname: East-Palmer
authors.forename: M W
authors.initials: MW
authors.lastname: Szkudlinski
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: N R
authors.initials: NR
authors.lastname: Thotakura
authors.forename: B D
authors.initials: BD
authors.lastname: Weintraub
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002417:Cattle; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010902:Pituitary Gland / Q000737:chemistry; D011863:Radioimmunoassay; D051381:Rats; D011994:Recombinant Proteins; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine