caa a22 4500 465805620 CHVBK 20180323112103.0 cr unu---uuuuu 170327e19900201xx s 000 0 eng 10.1007/BF03349534 doi (NATIONALLICENCE)springer-10.1007/BF03349534 Acute withdrawal of short-term or prolonged L-triiodothyronine administration to thyroidectomized rats results in similar rapid increases in TSHβ mRNA [Elektronische Daten] [Douglas Ross, A. Cohen] In pian, following the treatment of hyperthyroidism, or the withdrawal of prolonged suppressive thyroid hormone therapy, recovery from thyrotrope suppression may not occur until thyroid hormone concentrations have been subnormal for several weeks. Short-term studies in rodents have demonstrated a rapid increase in TSH synthesis after the acute withdrawal of thyroid hormones. We treated thyroidectomized rats with supraphysiologic doses of 1-triiodothyronine (T3) for 67 days, then abruptly withdrew treatment and compared the time course of thyrotrope recovery to that in animals given T3 for only 10 days. Increases in TSHβ mRNA after abruptly stopping T3 were qualitatively similar in both groups. After short-term T3 administration, TSHβ mRNA was detectable on the second day after stopping T3 administration and rose an additional 10-fold by day 5. After prolonged T3 administration, TSHβ mRNA was barely detectable on the second day after stopping T3 administration, clearly detectable on the third day, and increased an additional 20-fold by day 7. Compared to animals who received T3 for only 10 days, suppression of the thyrotrope by T3 administration for 67 days resulted in a nonsignificant delay in TSHβ mRNA synthesis of 24 h or less following the abrupt withdrawal of thyroid hormone. It is possible that differences in rat and human thyrotrope responsiveness account for the apparently different biologic behavior. Italian Society of Endocrinology (SIE), 1990 Ross Douglas Thyroid Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 02114, Boston, MA, USA aut Cohen A. Thyroid Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 02114, Boston, MA, USA aut Journal of Endocrinological Investigation Springer International Publishing 13/2(1990-02-01), 177-180 0391-4097 13:2<177 1990 13 40618 https://doi.org/10.1007/BF03349534 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF03349534 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ross Douglas Thyroid Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 02114, Boston, MA, USA aut NATIONALLICENCE 700 1- Cohen A. Thyroid Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 02114, Boston, MA, USA aut NATIONALLICENCE 773 0- Journal of Endocrinological Investigation Springer International Publishing 13/2(1990-02-01), 177-180 0391-4097 13:2<177 1990 13 40618 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer