Reversible Inhibition of Mammary Gland Growth by Transforming Growth Factor-β

TLDR

Transforming growth factor‑β can stimulate or inhibit cell growth in vitro, yet its in vivo effects and physiological role remain largely unknown. The authors applied slow‑release TGF‑β‑containing plastic pellets to developing mouse mammary glands to assess its local impact. TGF‑β produced potent, reversible inhibition of mammary growth and morphogenesis while preserving normal histology, indicating it functions as a physiologically active growth regulator.

Abstract

Transforming growth factor-β (TGF-β) can stimulate or inhibit growth of cells in vitro, as well as induce the transformed phenotype. Although widely distributed in animal tissue, the effects of TGF-β in vivo are largely unknown, and a physiological role for the peptide hormone has not been demonstrated. The effect of TGF-β on developing epithelial tissue in situ was studied by using slow-release plastic pellets containing TGF-β to treat developing mouse mammary gland. Powerful inhibition of mammary growth and morphogenesis was observed. This growth-inhibited mammary tissue was histologically normal, and the inhibitory effect was fully reversible. Under the conditions of these experiments, TGF-β displayed many of the characteristics expected of a physiologically active growth-regulatory molecule.