Structure-activity relation of thyroid hormone analogues and tissue epidermal growth factor concentrations in neonatal and adult mice.

We have shown a positive correlation between the epidermal growth factor concentration in neonatal mouse skin and prior treatment with thyroxine (T4) or triiodothyronine (T3). The results of the present study indicate similar activity of other levorotatory iodothyronine analogues and suggest the following scale of decreasing potency: T3, triiodothyroacetic acid, triiodothyropropionic acid, T4, reverse T3, and diiodothyronine. Metabolically inactive analogues (reverse T3, diiodothyronine) have no effect on skin EGF levels. A similar response pattern was observed in the adult, female mouse submandibular gland, except that T4 seemed relatively more effective.