Regulation of Transforming Growth Factor-Alpha Expression by Thyroid Hormone during the Post-Natal Development of Rat Submandibular and Sublingual Salivary Glands

Transforming Growth Factor-alpha is a mitogen peptide performing diverse cellular functions and is immunolocalized in ductal epithelium of salivary glands. The development of salivary glands is under the influence of various hormones including Triiodothyronine hormone (T3). Submandibular gland of rat is an excellent model to study salivary gland organogenesis. The study is designed to understand T3 mediated regulation of TGF-alpha expression during postnatal salivary gland development as it is currently unknown. Twelve male rats were taken at week three and twelve at week seven and divided into control and experimental groups. Control rats were given normal saline while experimental rats were given T3 at a dose of 1mg/kg body weight. All the animals were sacrificed on 15th day. Weight of each rat was calculated at the time of T3 administration. Body weight of experimental animals increased at a slow rate as compared to the control animals. The immunohistochemical expression of TGF-alpha in ductal epithelium of both salivary glands was decreased in experimental group sacrificed at 5 weeks. However no significant change was observed in TGF-alpha expression in ductal epithelium of salivary glands in rats sacrificed at 9 weeks. T3 has a temporal effect on TGF-alpha expression during early postnatal rat salivary gland development.