NCOA1 and obesity due to melanocortin 4 receptor deficiency: As well as developing obesity, SRC-1 knockout mice exhibit resistance to thyroid hormone (RTH) (11) and partial resistance to estrogen, progesterone, and testosterone (12), manifesting as decreased growth and development of the uterus, ovaries, mammary glands, and testes (12) and loss of trabecular bone mass (13).