Evidence of Thyrotropin-Releasing Hormone (TRH) and TRH-Binding Sites in Human Nonsecreting Pituitary Adenomas
- 1 November 1987
- journal article
- other
- Published by The Endocrine Society in Journal of Clinical Endocrinology & Metabolism
- Vol. 65 (5) , 1014-1019
- https://doi.org/10.1210/jcem-65-5-1014
Abstract
Immunoreactive TRH (IR-TRH) and TRHbinding sites were sought in nonsecreting pituitary adenomas. [3H]TRH bound specifically to cellular membranes from 11 of 12 such adenomas studied, with a dissociation constant (Kd) of 50 ± 5 (±sem) nmol/L and a maximum number of binding sites of 76 ± 16 fmol/mg membrane protein (range, 32-229 fmol/mg protein). IR-TRH was detected in all 8 of the tumors in which it was sought. The identity of the IR-TRH was verified by high pressure liquid chromatography. The tumor IR-TRH concentration varied from 45-248 fmol/mg cell protein (mean, 109 ± 28 fmol/mg cell protein), about half that in normal human pituitary 229 ± 55 fmol/mg protein). There was no correlation between the number of binding sites and the IR-TRH content. The role of TRH in nonsecreting pituitary adenomas is unknown at this time.Keywords
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