Breast development extension adrenocorticotropic hormone (ACTH)), and thyroid hormones such as thyroxine (and by extension thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH)) also play permissive but less well-understood/poorly-characterized roles in breast development during both puberty and pregnancy, and are required for full functional development. Leptin has also been found to be an important factor in mammary gland development, and has been found to promote mammary epithelial cell proliferation. In contrast to the female-associated sex hormones, estrogen and progesterone, the male-associated sex hormones, the androgens, such as testosterone and dihydrotestosterone (DHT), powerfully suppress the action of estrogen in the breasts. At least one
Transgender hormone therapy (male-to-female) lower portion of the cheeks fills in. HRT causes a reduction in muscle mass and distribution towards female proportions. Male-to-female hormone therapy causes the hips to rotate slightly forward because of changes in the tendons. Hip discomfort is not uncommon. This can cause a reduction in total body height. If estrogen therapy is begun prior to pelvis ossification, which occurs around the age of 25, the pelvic outlet and inlet open slightly. The femora also widen, because they are connected to the pelvis. The pelvis retains some masculine characteristics, but the end result of HRT is wider hips than a