- Thyroid hormones are involved in insulin-like growth factor-I (IGF-I) production by stimulating hepatic growth hormone receptor (GHR) gene expression in the chicken. Tsukada, A., Ohkubo, T., Sakaguchi, K., Tanaka, M., Nakashima, K., Hayashida, Y., Wakita, M., Hoshino, S. Growth Horm. IGF Res. (1998)