M E J replied: "testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid. In both men and women, testosterone plays a key role in health and well-being as well as in sexual functioning. Estrogens (alternative spellings: oestrogens or œstrogens) are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone. Estrogens are used as part of some oral contraceptives, in estrogen replacement therapy of postmenopausal women, and in hormone replacement therapy for transwomen. Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestogens, and is the major naturally occurring human progestogen. Follicle-stimulating hormone (FSH) is a hormone synthesised and secreted by gonadotropes in the anterior pituitary gland. FSH and LH act synergistically in reproduction: In women, in the ovary FSH stimulates the growth of immature Graafian follicles to maturation. As the follicle grows, it releases inhibin, which shuts off the FSH production. In men, FSH enhances the production of androgen-binding protein by the Sertoli cells of the testes, and is critical for spermatogenesis. Luteinizing hormone (LH) is a hormone synthesized and secreted by gonadotropes in the anterior lobe of the pituitary gland. In concert with the other pituitary gonadotropin follicle stimulating hormone (FSH) it is necessary for proper reproductive function: In the female, an acute rise of LH – the LH surge – triggers ovulation. In the male, where LH had also been called Interstitial Cell Stimulating Hormone (ICSH), it stimulates Leydig cell production of testosterone. Prolactin (PRL) is a peptide hormone primarily associated with lactation. In breastfeeding, the act of an infant suckling the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis, in preparation for the next feed. Oxytocin, a similar hormone, is also released, which triggers milk let-down. Oxytocin (quick birth) is a mammalian hormone that also acts as a neurotransmitter in the brain. In women, it is released in large amounts after distension of the cervix and vagina during labor, and after stimulation of the nipples, facilitating birth and breastfeeding, respectively. It is occasionally misspelled as oxytoxin. Synthetic oxytocin is sold as medication under the trade names Pitocin and Syntocinon as well as generic oxytocin. In humans, oxytocin is thought to be released during hugging, touching, and orgasm in both sexes. In the brain, oxytocin is involved in social recognition and bonding, and may be involved in the formation of trust between people and generosity."