Thyroid hormone effects on skin and hepatic epidermal growth factor concentrations in neonatal and adult mice

Tissue concentrations of mouse epidermal growth factor (skin, submandibular gland and liver) are compared in control and thyroxine-treated neonatal and adult animals. The results identify an early onset thyroid-induced augmentation of EGF levels in neonatal skin with continuation of hormone responsiveness into adult life. Hepatic EGF levels are shown to be low and, unlike skin and submandibular gland, are not augmented by T4. The significance of hormonal modulation of nonsalivary growth factor concentrations is discussed.