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 (female-to-male) Transgender hormone therapy (female-to-male) Transgender hormone therapy of the female-to-male (FTM) type, also known as masculinizing hormone therapy, is a form of hormone therapy and sex reassignment therapy which is used to change the secondary sexual characteristics of transgender people from feminine (or androgynous) to masculine. It is one of two types of transgender hormone therapy (the other being male-to-female), and is predominantly used to treat transgender men and other transmasculine individuals. Some intersex people also receive this form of therapy, either starting in childhood to confirm the assigned sex or later if the assignment proves to be incorrect. The