In this blog post, we will look at how obesity affects hormone balance and how this changes reproductive function.

Reproductive function and the role of hormones

Our body’s reproductive function is precisely regulated by the action of various hormones. In both men and women, stimulation from hormones secreted by the hypothalamus causes two types of gonadotropin-releasing hormones to be secreted from the anterior pituitary gland. These two hormones are luteinizing hormone (LH) and follicle-stimulating hormone (FSH). They act on their respective gonads and are involved in the synthesis of sex hormones and the maturation of germ cells.

Male reproductive function and hormone action

In males, luteinizing hormone (LH) stimulates the Leydig cells in the testicles to promote the synthesis of male hormones (testosterone). The male hormones produced in this way are transported throughout the body via the bloodstream or move to the Sertoli cells in the testicles.
These cells are also stimulated by follicle-stimulating hormone (FSH), which helps spermatogonia (the precursor cells of sperm) mature into mature sperm.
The sperm then leave the testicles and travel to the epididymis, where they mature. During this process, male hormones activate the epididymis, enabling the sperm to become motile and capable of fertilization. As you can see, male hormones are involved in a wide range of processes, from sperm production to maturation and functional development.

Female reproductive function and hormone action

In women, cooperation between hormones is also key. Luteinizing hormone (LH) acts on the follicular cells of the ovaries to increase the synthesis of male hormones. These male hormones then move to the granulosa cells, where they are converted into female hormones (estrogens) by the enzyme aromatase, which is stimulated by follicle-stimulating hormone (FSH).
The female hormones produced help the follicular cells mature and develop into eggs, inducing ovulation. At the same time, they act on the endometrium to create an environment conducive to pregnancy. These changes, which cause the endometrium to thicken and become rich in nutrients, are preparatory steps for the implantation of a fertilized egg.

Mechanism of sex hormone regulation

In order to maintain normal reproductive function, it is very important to maintain a balance of sex hormone levels in the blood. In men, testosterone synthesized in the testicles affects the hypothalamus and pituitary gland, while in women, estrogen and progesterone produced in the ovaries affect the hypothalamus and pituitary gland.
These sex hormones act on the hypothalamus to regulate the secretion of gonadotropin-releasing hormone (GnRH), which in turn regulates the secretion of LH and FSH in the pituitary gland, forming a negative feedback loop. This feedback mechanism maintains the homeostasis of hormone concentrations.

Effects of obesity on reproductive function

However, as obesity progresses, this delicate hormonal balance begins to be disrupted. Adipose tissue is more than just a storehouse for energy; it is actively involved in hormone metabolism. In particular, adipocytes contain an enzyme called aromatase, which converts male hormones into female hormones.
When obesity causes an increase in the size and number of fat cells, the action of aromatase is also strengthened, increasing the amount of male hormones converted to female hormones. As a result, both men and women tend to have higher levels of female hormones in their blood.

Changes in reproductive function in obese men and women

In obese men, the increase in female hormones affects the regulatory mechanisms of the hypothalamus and pituitary gland. The negative feedback effect of female hormones suppresses the secretion of gonadotropin-releasing hormone, which reduces sperm production in the testicles and the secretion of male hormones. This can lead to a decrease in sperm count or motility, resulting in reduced reproductive function.
On the other hand, obese women experience more complex changes. Female hormones produced or stored in fat cells temporarily increase blood concentrations, but fat tissue reabsorbs and stores them, so there are no significant changes in the long term.
However, problems arise in hormone regulation between the pituitary gland and the ovaries. Increased female hormones stimulate the pituitary gland, promoting LH secretion, which in turn increases the synthesis of male hormones in the ovaries. At the same time, FSH secretion is suppressed, which reduces the activity of aromatase in granulosa cells. Eventually, female hormone production decreases, male hormones accumulate in the ovaries, and the hormonal balance is disrupted.
These changes directly affect the maturation process of eggs, preventing ovulation from occurring properly. A typical disease that results from this is polycystic ovary syndrome (PCOS). This syndrome is characterized by the presence of many immature follicles, which can lead to irregular menstruation, reduced ovulation, and in severe cases, infertility.

Conclusion: For healthy reproductive function

Hormonal balance is essential for maintaining normal reproductive function, and obesity is one of the main factors that can disrupt this balance. It is important to recognize that adipose tissue is deeply involved in hormone metabolism and to maintain a healthy weight through lifestyle changes.
A healthy lifestyle, including a balanced diet, regular exercise, and stress management, is not only important for appearance and weight management, but also plays a key role in maintaining reproductive health and overall hormonal balance. It is important to remember that reproductive decline is not simply a matter of age, but is directly linked to lifestyle habits.