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A.M. PASCUAL-LEONE ANAL. REAL ACAD. FARM.
acción directa de las hormonas tiroideas modulando la actividad desyodásica en hígado y
por consiguiente los niveles de T3 hepáticos y plasmáticos.
Palabras clave: Hormonas tiroideas.- Factores de crecimiento.- insulina.- Metabolismo.
SUMMARY
Interrelationships between thyroid hormones and (IGFs)
Thyroid hormones and insulin-like growth factors (IGFs) play a key role in growth
regulation during immature stages of life. Both endocrine factors are involved in the
regulation of metabolism and their secretion is decreased in a situation of undernutrition.
Although the interaction between thyroid hormones and IGFs represents a complex
question, its study has produced interesting data to Biology of Development and the current
Molecular Endocrinology. The interrelationship between classic hormones and growth
factors, especially during periods of enhanced cell proliferation such as perinatal
development, remains largely unknown.
The present work shows the IGFs regulation when thyroxine (T4) is administered
to neonatal and adult rats submitted to two experimental models: a) hypothyroidism
induced by thyroidectomy, and b) diabetes induced by streptozotocin administration. Serum
levels of IGF-I and -II in neonatal rats and IGF-I in adults as well as their liver mRNA
expression were determined. It is concluded that, in addition to the mediating effect of
insulin in neonatal rats and of GH in adults, thyroid hormones seem to have a direct effect
on IGFs secretion by regulating liver 5´-deiodinase and, consequently, inducing changes in
liver synthesis and plasma levels of T3.
Key words: Thyroid hormones.- Growth factors.- Insulin.
1. INTRODUCCION
El estudio de la interacción entre hormonas tiroideas y factores de
crecimiento similares a la insulina (IGFs) tiene una gran importancia como
aporte de conocimiento en dos vertientes de investigación biomédica muy
interesantes como son la Biología del Desarrollo y la Endocrinología
Molecular actual. Vamos a dividir la exposición en las partes reseñadas en
tabla 1.
2
