title: Secretion and binding of insulin-like growth factor-I by a human medullary-thyroid carcinoma cell-line.
abstract: The TT human medullary thyroid carcinoma cell line secretes a 7.5 kD species with insulin-like growth factor (IGF-I) immunoreactivity and HPLC mobility and expresses IGF-I mRNA. Conditioned medium also contained IGF-binding activity with a pattern of displacement of [I-125]-IGF-I characteristic of IGF binding proteins. Western ligand analysis and immunobloting with anti-IGFBP4 antiserum identified a 34 kD IGF-I binding species. Northern analysis identified a 2.1 kb IGFBP4 mRNA species. Cell surface binding of [I-125]-IGF-I identified Type I IGF receptors. TT cells constitute a useful model to study the IGF-I autocrine system in the transformed state.
authors.affiliation: VET ADM MED CTR,DEPT MED,DIV ENDOCRINOL & HYPERTENS,MED SERV 111W,10701 E BLVD,CLEVELAND,OH 44106. CASE WESTERN RESERVE UNIV,SCH MED,CLEVELAND,OH 44106.
authors.forename: C
authors.initials: C
authors.lastname: Bethel
authors.forename: H
authors.initials: H
authors.lastname: Saadi
authors.forename: W
authors.initials: W
authors.lastname: Hout
authors.forename: J
authors.initials: J
authors.lastname: Vitullo
authors.forename: D
authors.initials: D
authors.lastname: Aron