Testosterone Production

Animation Description: This animation represents a visual interpretation of the production of testosterone and is not indicative of clinical effectiveness.

The hypothalamus releases gonadotropin-releasing hormone (GnRH) in pulses every 60 to 90 minutes to stimulate the pulsatile release of luteinizing hormone (LH) from the pituitary gland into the bloodstream.

LH binds the LH receptor on the Leydig cells of the testes.

Binding initiates a cascade of events which include the conversion of cholesterol (depicted as LDL here) to pregnenolone followed by a series of reactions, which convert pregnenolone to testosterone.

Testosterone, secreted by the testes, diffuses into the peripheral circulation to be carried to target tissues.

In liver, muscle and adipose tissue, testosterone binds directly to its androgen receptor (AR) to exert its biological effect.

In skin, hair, the prostate gland and gonadal tissue, testosterone must be converted to dihydrotestosterone (DHT) by 5-alpha-reductase in order to bind the androgen receptor.

In bone and brain, testosterone is converted by aromatization to estradiol (E2), which binds the estrogen receptor (E2R) to carry out its effects.

There is an accompanying accredited online resource, http://www.ManagingTD.ca that contains the learning materials, as well as videos, animations & an interactive algorithm.

The Estrogen Receptor Hormonal Mechanisms

Estrogen receptor refers to a group of receptors which are activated by the hormone 17β-estradiol (estrogen). Two types of estrogen receptor exist: ER which is a member of the nuclear hormone family of intracellular receptors and the estrogen G protein coupled receptor GPR30 (GPER), which is a G-protein coupled receptor. This article refers to the nuclear hormone receptor ER.

The main function of the estrogen receptor is as a DNA binding transcription factor which regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding.

Estrogen receptor Molecular and cellular mechanism,Steroid hormones are chemical substances secreted by glands in the abdomen with involved in the regulation of variety of the functions including sodium balace,metabolism and reproductive functions.For example

Hormones at puberty

A boy reaches puberty when the hypothalamus directs the pituitary gland to increase the secretion of the trophic hormones--luteinizing hormone, follicle-stimulating hormone and adrenocorticotrophic hormones. These act on the testes to start the production of sperm and on the adrenal cortex and testes to produce male hormones, or androgens. Testosterone, the most important androgen, promotes and controls the devlopment of the sex organs and such secondary sexual characteristics as pubic and facial hair. In a girl, the trophic hormones stimulate the ovaries and adrenal glands to secrete androgens that control the shape of the female body. The ovarian hormones, progesterone and estrogen, initiate menstruation.