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Suppression of thyrotropin by 3,5-dimethyl-3'-isopropyl-L-thyronine in euthyroid and hypothyroid rats.
Endocrinology. 1980 Oct; 107(4):1050-4.E

Abstract

The effect of 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT) a nonhalogenated thyroid hormone analog, on plasma and pituitary TSH levels was studied in euthyroid and 5-day-thyroidectomized (T-5d) rats. The minimal dose of DIMIT which suppressed basal plasma TSH for a 24-h period was 5.3 micrograms/100 g BW in the euthyroid rats and 5.2 micrograms/100 g BW in the T-5d group. The equipotent doses of T3 were 1.0 and 1.5 micrograms/100 g BW, respectively. Thus, the apparent DIMIT to T3 molar ratio ranged from 6.6 in the hypothyroid to 10 in the euthyroid group. The suppression of TRH-induced TSH release in the euthyroid rats required a high dose of DIMIT (9.2 micrograms/100 g BW), resulting in a DIMIT to T3 molar ratio of 17. Time-course studies comparing the effects of equipotent doses of DIMIT and T3 on TSH release rates in euthyroid and T-5d rats have shown a maximal suppression by 3--24 h after the administration of both T3 and DIMIT. However, the recovery from the effect was slower after T3. TSH synthesis in the T-5d group was similarly suppressed by DIMIT and T3. DIMIT has significant thyromimetic activity in euthyroid and hypothyroid rats, as evidenced by the suppresion of TSH synthesis and release.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7408758

Citation

Melmed, S, et al. "Suppression of Thyrotropin By 3,5-dimethyl-3'-isopropyl-L-thyronine in Euthyroid and Hypothyroid Rats." Endocrinology, vol. 107, no. 4, 1980, pp. 1050-4.
Melmed S, Spira O, Gordon A, et al. Suppression of thyrotropin by 3,5-dimethyl-3'-isopropyl-L-thyronine in euthyroid and hypothyroid rats. Endocrinology. 1980;107(4):1050-4.
Melmed, S., Spira, O., Gordon, A., Gross, J., Jorgensen, E. C., & Hershman, J. M. (1980). Suppression of thyrotropin by 3,5-dimethyl-3'-isopropyl-L-thyronine in euthyroid and hypothyroid rats. Endocrinology, 107(4), 1050-4.
Melmed S, et al. Suppression of Thyrotropin By 3,5-dimethyl-3'-isopropyl-L-thyronine in Euthyroid and Hypothyroid Rats. Endocrinology. 1980;107(4):1050-4. PubMed PMID: 7408758.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Suppression of thyrotropin by 3,5-dimethyl-3'-isopropyl-L-thyronine in euthyroid and hypothyroid rats. AU - Melmed,S, AU - Spira,O, AU - Gordon,A, AU - Gross,J, AU - Jorgensen,E C, AU - Hershman,J M, PY - 1980/10/1/pubmed PY - 1980/10/1/medline PY - 1980/10/1/entrez SP - 1050 EP - 4 JF - Endocrinology JO - Endocrinology VL - 107 IS - 4 N2 - The effect of 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT) a nonhalogenated thyroid hormone analog, on plasma and pituitary TSH levels was studied in euthyroid and 5-day-thyroidectomized (T-5d) rats. The minimal dose of DIMIT which suppressed basal plasma TSH for a 24-h period was 5.3 micrograms/100 g BW in the euthyroid rats and 5.2 micrograms/100 g BW in the T-5d group. The equipotent doses of T3 were 1.0 and 1.5 micrograms/100 g BW, respectively. Thus, the apparent DIMIT to T3 molar ratio ranged from 6.6 in the hypothyroid to 10 in the euthyroid group. The suppression of TRH-induced TSH release in the euthyroid rats required a high dose of DIMIT (9.2 micrograms/100 g BW), resulting in a DIMIT to T3 molar ratio of 17. Time-course studies comparing the effects of equipotent doses of DIMIT and T3 on TSH release rates in euthyroid and T-5d rats have shown a maximal suppression by 3--24 h after the administration of both T3 and DIMIT. However, the recovery from the effect was slower after T3. TSH synthesis in the T-5d group was similarly suppressed by DIMIT and T3. DIMIT has significant thyromimetic activity in euthyroid and hypothyroid rats, as evidenced by the suppresion of TSH synthesis and release. SN - 0013-7227 UR - https://www.unboundmedicine.com/medline/citation/7408758/Suppression_of_thyrotropin_by_35_dimethyl_3'_isopropyl_L_thyronine_in_euthyroid_and_hypothyroid_rats_ L2 - https://academic.oup.com/endo/article-lookup/doi/10.1210/endo-107-4-1050 DB - PRIME DP - Unbound Medicine ER -