Most of the major functions of the body are controlled via the release of chemical messengers called hormones. Synthesized in the endocrine system, hormones play a critical role in basic processes such as the regulation of mood, emotion, and hunger as well as larger systems like reproduction and growth.
Despite the dissimilarity between the male and female reproductive systems, the basic bodily functions and neurological responses that cause the secretion of the hormones associated with reproduction are essentially the same. With a wide range of effects in the body that aren’t strictly limited to reproduction, these hormones have a broad spectrum of properties that can contribute to everything from digestive health to immune system response and even cognitive function.
Introduction to Reproductive Hormones
One of the most important functions of hormones in the human body is the regulation of the reproductive system. While the reproductive hormones of women and men are fundamentally different, both are controlled through the synthesis and release of specific hormones. The hormones of the body associated with reproduction are regulated primarily from the hypothalamus and pituitary glands of both sexes, and the gonads— the testes in men, and ovaries in women.
Reproductive hormones can be broken down into three distinct categories— GnRH, FSH and LH hormones. GnRH hormones are released by the hypothalamus, stimulating the release of the latter two hormones. FSH, or follicle stimulating hormones and LH, or luteinizing hormone, are produced by the pituitary gland.
While the production of hormones are the same in both male and female bodies with regards to the function of the hypothalamus and pituitary glands, the effects of these hormones on bodily function differ between the sexes and rely upon hormones generated by the differing reproductive systems and their effect on the brain.
Male Reproductive Hormones
The three aforementioned hormones have a number of effects unique to the male. To understand what hormones control male reproductive function, it’s important to understand the method through which the body generates hormones.
In the male body, FSH is responsible for the production of sperm in the testes. LH binds to the leydig cells, located in the testicles, to stimulate testosterone production. Both of the secondary hormones are produced in the body in response to GnRH travelling to the pituitary gland, stimulating hormone secretion. Testosterone, the male hormone, is responsible for a wide range of secondary sexual characteristics in men such as muscle bone density, and hair thickness and distribution.
What are the Reproductive Glands That Produce Male Hormones?
While both LH and FSH are produced in the pituitary gland, GnRH is manufactured in the hypothalamus, located in the forebrain. External environmental factors cause sensory impulses that stimulate GnRH producing neurons in the brain. GnRH produced by these neurons travels through the brain to the pituitary gland, located below the hypothalamus, where it stimulates the secretion of both LH and FSH neurons.
Male hormones such as testosterone also contribute to sex drive and muscle tissue growth, while Inhibin produces a negative feedback to slow the release of FSH and GnRH when it isn’t needed.
Female Reproductive Hormones
The hormones in the female system are the same as those in the male system, with one exception. Consisting of GnRH, FSH and LH in the same manner as the male system, female hormones also include progesterone, which is responsible for preparing the uterine lining to receive a fertilized egg or alternatively triggering menstruation.
The primary female sex hormone is estrogen. Triggering the menstrual cycle and promoting the development of female secondary sexual characteristics, estrogen is primarily produced in the ovaries, but is also created in small amounts in the adrenal glands.
How do Female Reproductive System Hormones Work?
While GnRH is produced by the hypothalamus and travels to the pituitary gland to catalyze the production of LH and FSH in the same manner as the male body, the effects of the hormones differ. In Females, LH functions as a regulator of the ovulation cycle, and interacts with the hormonal systems of the body that prepare it for pregnancy.
FSH in the female body stimulates the growth of fluid filled sacs in the ovaries, called follicles, that contain developing eggs during pregnancy. GnRH also plays a different role in the female body— in the first half of the menstrual cycle, GnRH promotes the production of FSH, while in the latter causes the synthesis of LH.
The female system also relies upon two other hormones— oxytocin and prolactin. Oxytocin is critical in causing contractions during the childbirth process. Prolactin is a hormone unique to the female body, causing milk production.