Direct effects of protirelin (TRH) on cultured porcine thyrocytes.
In several cases of thyroid adenoma in which no TSH was detectable in the serum, a paradoxical decrease of PB123I and its conversion rate Q (PB123I/serum total radioactivity) was observed after infusion of protirelin (TRH). The possibile direct effect of TRH on thyrocytes was therefore studied in vitro. Porcine thyroid cells were cultured in NCTC-135 medium supplemented with a serum substitute and insulin. TRH and some of its analogs enhanced the incorporation of [3H]thymidine into DNA and the uptake of radioiodide into thyrocytes. In the presence of TSH, TRH did not stimulate radioiodine uptake, whereas incorporation of [3H]thymidine into DNA was not antagonized by TSH. Thus, in this culture system, TRH had a direct effect on both growth and metabolism of thyrocytes. TSH can modulate these effects.
Wahl
R
R
Medizinische Universitaetsklinik, Abt. IV, Tuebingen, FRG.
Brossart
P
P
Eizenberger
D
D
Schuch
H
H
Kallee
E
E
D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005347:Fibroblasts / Q000187:drug effects; D013552:Swine; D013936:Thymidine / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology*
D013973:Thyrotropin-Releasing Hormone; D004247:DNA; D013936:Thymidine