Type 2 iodothyronine deiodinase in skeletal muscle: effects of hypothyroidism and fasting.
J Clin Endocrinol Metab
; 94(6): 2144-50, 2009 Jun.
Article
en En
| MEDLINE
| ID: mdl-19293265
ABSTRACT
CONTEXT The iodothyronine deiodinases D1, D2, and D3 enable tissue-specific adaptation of thyroid hormone levels in response to various conditions, such as hypothyroidism or fasting. The possible expression of D2 mRNA in skeletal muscle is intriguing because this enzyme could play a role in systemic as well as local T3 production. OBJECTIVE:
We determined D2 activity and D2 mRNA expression in human skeletal muscle biopsies under control conditions and during hypothyroidism, fasting, and hyperinsulinemia.DESIGN:
This was a prospective study.SETTING:
The study was conducted at a university hospital. PATIENTS We studied 11 thyroidectomized patients with differentiated thyroid carcinoma (DTC) on and after 4 wk off T4( replacement and six healthy lean subjects in the fasting state and during hyperinsulinemia after both 14 and 62 h of fasting. MEAN OUTCOMEMEASURES:
D2 activity and D2 mRNA levels were measured in skeletal muscle samples.RESULTS:
No differences were observed in muscle D2 mRNA levels in DTC patients on and off T4 replacement therapy. In healthy subjects, muscle D2 mRNA levels were lower after 62 h compared to 14 h of fasting. Insulin increased mRNA expression after 62 h, but not after 14 h of fasting. Skeletal muscle D2 activities were very low and not influenced by hypothyroidism and fasting.CONCLUSION:
Human skeletal muscle D2 mRNA expression is modulated by fasting and insulin, but not by hypothyroidism. The lack of a clear effect of D2 mRNA modulation on the observed low D2 activities questions the physiological relevance of D2 activity in human skeletal muscle.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ayuno
/
Músculo Esquelético
/
Hipotiroidismo
/
Yoduro Peroxidasa
Tipo de estudio:
Etiology_studies
/
Observational_studies
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Risk_factors_studies
Límite:
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
J Clin Endocrinol Metab
Año:
2009
Tipo del documento:
Article
País de afiliación:
Países Bajos