The Intrinsic Activity of Thyroxine is Critical for Survival and Growth and Regulates Gene expression in Neonatal Liver.

CONCLUSION: T4 has intrinsic activity in vivo and is critical for survival and growth. At a physiological level, T4 per se can up- or down-regulate many T3 target genes in the neonatal liver. While most of these genes are also regulated by T3, subsets respond exclusively to T4 or demonstrate enhanced or normalized expression only in the presence of both hormones. These studies demonstrate for the first time a complex dependency on both T4 and T3 for normal mammalian growth and development. PMID: 32791885 [PubMed - as supplied by publisher]
Source: Thyroid : official journal of the American Thyroid Association - Category: Endocrinology Tags: Thyroid Source Type: research