What is Androgen Definition Types Functions and Mechanism of Action
Testes are present in human males. They are present in a pair. They are formed from the mesoderm of the endoderm. They are located in the scrotal sac and this sac is present outside the abdominal cavity. This scrotal sac is known as the scrotum. This scrotum is responsible for the production of sperms because sperms require 2-3 degree celsius less temperature than the body. These testes are developed in the abdomen but in the foetal stage, they get transferred to the scrotum. The hormones that are produced by them are called the androgen hormone. It is not necessary that only testes will produce hormones and they are present only in males, some amount of testosterone is even present in the female and that is responsible for giving some male-like characteristics. Dihydrotestosterone or testosterone is the major androgen. In this article, we will learn about what androgen means in detail.
Sertoli Cells
Sertoli cells are present in the testis. They help in the secretion of dihydrotestosterone. The function of Sertoli cells are:
The parts that are absorbed by the spermatozoa are absorbed by these Sertoli cells.
They release anti-mullerian factors. These factors prevent oviduct development in males.
The blood-testis barrier is formed by the androgen.
Androgen-binding protein is released by these Sertoli cells.
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Testes and Their Hormones
The testes are the primary sex organs and they also act as endocrine glands. As they function like endocrine glands, they can be called adrenal androgens. Seminiferous tubules are present in the testes. Interstitial and stromal tissues are also present in the testes. The process of formation of sperms is achieved by the seminiferous tubules. This helps in fulfilling the function of primary sex organs. Inside the seminiferous tubules, we have the Leydig cells and interstitial cells and these are present inside the spaces of seminiferous tubules. Androgen is steroid hormones that are produced by these Leydig cells and interstitial cells. Dihydrotestosterone is one of the major androgens. The luteinizing hormone influences the Leydig cells to secrete testosterone.
The Functions of the Androgen Hormone Are:
Muscular growth is stimulated by the androgens.
It helps in the male pattern of the external genitalia.
These androgens act on the androgens and they help in influencing male sexual behaviour.
Spermatogenesis is the process by which sperms are formed and these androgens help in stimulating that process.
The male accessory sex organs are developed with the help of these androgens.
Acne on the face is known as androgen acne.
Testosterone Functions
Testosterone is the strongest androgen and estrogen is a natural anti androgen.
The testes are descended with the help of testosterone.
It helps in the male pattern of development.
It helps in developing male sexual characteristics.
It helps in the maintenance of male sexual characteristics.
The process of spermatogenesis is stimulated by testosterone
They help in a growth spurt.
Disorders of Testosterone
The ovaries produce estrogen. It can function as an anti androgen hormone. When the androgens or the testosterone is not present in sufficient quantities, then we face some issues.
They are:
Eunuchoidism: This condition is seen when there is no testes secretion. When this condition occurs, then secondary sex organs such as the penis and testes remain small and dysfunctional. The sperms are also produced. Some secondary sexual characteristics such as beard and moustaches are also not present in these types of males.
Gynaecomastia: When breast tissues are developed in males then this condition is known as gynecomastia. This condition is developed when the androgen and estrogen hormones are not present in proper ratios as they are required by the body. Sometimes when there is a decrease in the amount of testosterone even then this condition can occur. The removal of testis from the males can also result in this condition. Dheas PCOS (dehydro epi androsterone)hormone is present in the ovary of the females. Estrogen is one of the strongest natural anti androgens.
Spermatogenesis
It Occurs in Four Stages:
Spermatocytogenesis: The spermatogonia present on the wall of the seminiferous tubules multiply by mitotic division and increase in numbers. Each spermatogonium is a diploid containing 46 chromosomes.
Meiosis-I: A primary spermatocyte is diploid with 44+ XY chromosomes. It completes the primary meiotic division resulting in the formation of two equal, haploid cells called secondary spermatocytes which have 23 chromosomes.
Meiosis-II: In this stage, the spermatids are reduced to 23 in number.
Spermiogenesis: By the end of spermiogenesis, 4 haploid sperms are produced.
FAQs on Androgen Hormones Structure Functions and Role in the Body
1. What is an androgen in biology?
An androgen is a group of steroid hormones that promote the development and maintenance of male characteristics in vertebrates. Androgens are synthesized mainly in the testes in males and in smaller amounts in the ovaries and adrenal glands in females. They play key roles in sexual differentiation, reproductive function, and secondary sexual characteristics such as facial hair and deep voice.
2. What is the main androgen hormone in humans?
The main androgen hormone in humans is testosterone. Testosterone is produced primarily by the Leydig cells of the testes in males and in smaller amounts by the ovaries and adrenal cortex in females. It regulates sperm production, muscle mass, bone density, libido, and the development of male secondary sexual characteristics.
3. What is the function of androgens in the body?
The primary function of androgens is to control male sexual development and reproductive function. Their major roles include:
- Stimulating development of male reproductive organs during embryonic growth
- Initiating spermatogenesis at puberty
- Promoting secondary sexual characteristics such as body hair and voice deepening
- Maintaining muscle mass, bone density, and red blood cell production
In females, androgens also contribute to libido and overall hormonal balance.
4. How are androgens produced in the human body?
Androgens are produced from cholesterol through a series of enzymatic reactions in endocrine glands. The process involves:
- Conversion of cholesterol into steroid precursors in the adrenal cortex and gonads
- Synthesis of weaker androgens such as dehydroepiandrosterone (DHEA)
- Conversion into stronger androgens like testosterone
In males, the hypothalamic–pituitary–gonadal (HPG) axis regulates androgen production via hormones such as GnRH and LH.
5. What is the difference between androgens and estrogens?
The main difference between androgens and estrogens is that androgens promote male traits while estrogens promote female traits. Key distinctions include:
- Androgens (e.g., testosterone) drive male sexual development and spermatogenesis
- Estrogens (e.g., estradiol) regulate the menstrual cycle and female reproductive development
- Both are steroid hormones derived from cholesterol
Importantly, both males and females produce both hormones, but in different concentrations.
6. What is the androgen receptor and how does it work?
The androgen receptor (AR) is a nuclear receptor protein that binds androgens and regulates gene expression. Its mechanism involves:
- Binding of testosterone or dihydrotestosterone (DHT) to the receptor in the cytoplasm
- Activation and movement of the receptor–hormone complex into the nucleus
- Binding to specific DNA sequences to control transcription of target genes
This process allows androgens to influence cell growth, differentiation, and reproductive function.
7. What are examples of androgens?
Common examples of androgens include testosterone and related steroid hormones. Major examples are:
- Testosterone – the primary male sex hormone
- Dihydrotestosterone (DHT) – a more potent derivative of testosterone
- Androstenedione – a precursor hormone
- Dehydroepiandrosterone (DHEA) – a weak androgen from the adrenal glands
These hormones vary in strength and biological activity.
8. What happens when androgen levels are too high?
High androgen levels can cause excessive development of male characteristics and hormonal imbalance. Effects may include:
- In males: acne, aggression, and risk of infertility if levels are abnormally elevated
- In females: hirsutism, acne, irregular menstruation, and conditions like polycystic ovary syndrome (PCOS)
Excess androgens may result from endocrine disorders or adrenal abnormalities.
9. What happens when androgen levels are too low?
Low androgen levels lead to reduced development or maintenance of male sexual traits and reproductive function. In males, this may cause:
- Decreased libido
- Reduced muscle mass and bone density
- Impaired spermatogenesis
In females, low androgens can contribute to reduced sexual desire and fatigue. Chronic deficiency in males is sometimes referred to as hypogonadism.
10. What is the role of androgens during puberty?
During puberty, androgens trigger the development of secondary sexual characteristics and reproductive maturity. In boys, increased testosterone leads to:
- Growth of the testes and penis
- Onset of sperm production
- Deepening of the voice
- Growth of facial and body hair
- Increase in muscle mass and height
This surge in androgens is regulated by activation of the hypothalamic–pituitary–gonadal axis.
