Changes

===Progesterone (P₄)===

===Progesterone (P₄)===

Progesterone is a steroid hormone that is produced by the corpus luteum and the placenta. In males the target tissues are the accessory sex glands, the tunica dartos (scrotum), the seminiferous tubules and skeletal muscles. In females the target tissues are the uterine endometrium, the mammary gland, the myometrium and the hypothalamus. Progesterone results in increased endometrial secretions and inhibits the release of GnRH in females. It also inhibits female reproductive behaviour as well as acting to maintain a pregnancy. Progesterone has no primary action in the male.

Progesterone is a steroid hormone that along with oestrogens is based on a cholesterol molecule. produced by the corpus luteum and the placenta using cholesterol as the base molecule. Progesterone is produced in the [[Corpus_Luteum_-_Anatomy_%26_Physiology|corpus luteum]]. More detailed information regarding corpus luteum [[Corpus_Luteum_Formation_-_Anatomy_%26_Physiology|formation]] and [[Corpus_Luteum_Regression_-_Anatomy_%26_Physiology|regression]] please use the links. Progesterone prepares the uterus for reception of fertilised oocytes and is transported via the blood bound to plasma proteins. Progesterone also prepares the mammary tissues for milk production as well as inhibiting female reproductive behaviours associated with oestrous.

Once near term, the concentration of progesterone decreases, altering the ratio between progesterone and oestrogen. This stimulates myometrial activity and prepares the uterus for parturition.

 

===Testosterone (T)===

===Testosterone (T)===

The male sex hormone is called testosterone and this hormone is required for [[Spermatogenesis_and_Spermiation_-_Anatomy_%26_Physiology|spermatogenesis]]. Testosterone is a steroid hormone that is produced in the leydig cells within the testes. A relatively high concentration of testosterone is maintained within the testicular tissue and testosterone is circulated around the body by diffusion of the hormone from the spermatic cord into the testicular veins and arteries. The primary action of testosterone is anabolic growth, spermatogenesis promotion and promotion of secretion from the accessory sex glands.

The male sex hormone is called testosterone and this hormone is required for [[Spermatogenesis_and_Spermiation_-_Anatomy_%26_Physiology|spermatogenesis]]. Testosterone is a steroid hormone that is produced in the leydig cells within the testes. A relatively high concentration of testosterone is maintained within the testicular tissue and testosterone is circulated around the body by diffusion of the hormone from the spermatic cord into the testicular veins and arteries. The primary action of testosterone is anabolic growth, spermatogenesis promotion and promotion of secretion from the accessory sex glands.