Leptin and reproductive function

Today the problem of obesity is so pressing that many are talking about an epidemic. The number of people who are overweight is growing everywhere, and many of them are women of reproductive age. Statistically, one-third of young women are obese and another quarter are overweight. In this article you will learn about the dangers of such a situation.


  1. How overweight affects reproduction.
  2. Triggers of obesity.
  3. Leptin resistance and reproduction.
  4. Insulin resistance.
  5. The combination of high insulin and leptin in the blood.
  6. To summarize.

How overweight affects reproduction

Among metabolic disorders one of the first places belongs to obesity, which leads to serious complications, including – puberty with deviations from the norm, which is especially noticeable in girls and later leads to female infertility. In the human body, extra pounds disrupt the normal functioning of virtually all organs and tissues. They are the triggers of a large number of serious diseases, especially in the reproductive system. Often obesity is a trigger for hyperplasia of the mucous membranes of the female reproductive organs and cancer of the endometrium, cervix, ovaries, breasts. Men are not left out, they form prostate cancer, rectal cancer.

First of all, women may experience menstrual disorders, infertility, and endometrial hyperplasia. The predominant type of female genital dysfunction is oligomenorrhea. At the onset of pregnancy, obesity provokes the development of diabetes, which is difficult to correct, dangerous for the fetus and the mother. Possible delay in fetal development of the fetus, a premature detachment of the placenta. There is a high probability of cesarean section, birth trauma of both the mother and the newborn, stillbirth, high maternal mortality. There is a risk of metabolic disorders in the newborn and in the future when the baby grows up.

Triggers of obesity

The main cause of extra pounds is excess body fat. Lipids play a crucial role in controlling energy homeostasis, insulin sensitivity through glucose and lipid metabolism, protein and hormone secretion.

Leptin is a peptide hormone that contains 167 amino acids, or rather their residues. It is synthesized by fat cells, so its amount is always proportional to the amount of adipose tissue in the body. Leptin reduces the body’s interest in food by affecting the satiety center localized in the hypothalamus. Based on recent clinical studies, leptin regulates fatty acid homeostasis, thus saving tissue from lipotoxicosis.

It has been suggested that the main task of leptin is to control energy balance as a signal to block unnecessary fat cumulation. This function is aimed mainly at preventing the minimization of energy reserves in the body, more than at increasing them. Thus, it prevents the development of obesity. Most obese patients have high levels of leptin in the blood stream and, unfortunately, leptin resistance.

Leptin resistance and reproduction

Today, leptin resistance is understood as resistance to the influence of leptin in all biochemical processes in the body. Its mechanisms are not fully understood.

Presumably, leptin resistance increases peroxidation of free fatty acids, which in theory is quite capable of activating the formation of lipotoxic disorders, including insulin resistance, endothelial dysfunction, oxidative stress. Because of leptin resistance and hyperleptinemia menstrual cycle is disturbed, there is a failure in the synthesis of steroid hormones in the granules of the ovarian cells, anovulation occurs, the hypothalamic-pituitary-ovarian system does not work properly.

In womens organism, leptin can directly control reproductive function. It is an indicator of nutritional status, which is important for oocyte fertilization and successful pregnancy. If leptin is low, its administration leads to an increase in gonadotropin and estradiol concentrations. Luteinizing hormone production correlates with leptin levels and drops with prolonged starvation. In the periphery, leptin conducts the expression of theca and granulosa cells from the ovarian stroma, fallopian tubes, and endometrium. At the same time, leptin activates gonadotropins, insulin and insulin-like growth factor, directing them to steroidogenesis in ovarian tissues and oocyte maturation.

Low plasma levels of another adiponectin hormone, adiponectin, precede insulin resistance. This hormone controls the synthesis of other bioactive substances and gene expression in the somato- and gonadotrophs of the pituitary gland, blocking the secretion of luteinizing hormone but not affecting follicle-stimulating hormone levels.

Insulin resistance

In most cases, obesity is combined with insulin resistance, high blood pressure and dyslipidemia. All together, this is the metabolic syndrome. Adiponectin increases tissue sensitivity to insulin, and fat cell proteins are involved in the development of insulin resistance and initiate the processes of inflammation and thrombosis.

Insulin resistance is affiliated with hyperinsulinemia, which is another characteristic of obesity that leads to infertility. The mechanisms of the influence of these triggers on reproductive function are not completely clear, but it is assumed that the main role is attributed to adipose tissue and disruption of the functional state of lipocytes.

One of the complications of insulin resistance and hyperinsulinemia is hyperandrogenism as a result of ovarian malfunction. This condition occurs against the background of excessive androgen secretion, which affects the target tissues. The particular urgency of the problem lies in the fact that reproductive dysfunction in this case may be affiliated with cancer. At the ovarian level, androgen excess causes stimulation of steroid synthesis in granulosa and theca cells, which activates sensitivity of pituitary gonadotrophs to hypothalamic gonadotropin-releasing hormone. This, in its turn, activates steroid synthesis in the ovaries. The result of these processes is hyperandrogenism, which negatively affects folliculogenesis.

On the other hand, a maximum of androgens in the periphery and their infiltration of adipose tissue provokes a high concentration of estrogens, which leads to a block of normal gonadotropin secretion and, as a result, to a dysregulation of ovulation. There is a hypothesis of a significant role of obesity combined with high insulin levels in the development of polycystic ovaries. The notorious insulin resistance also plays a role. However, hyperinsulinemia can develop without obesity, so extra pounds can be considered only as one of the factors contributing to the development of insulin resistance.

Clinicians emphasize that the frequent combination of hyperandrogenism and insulin resistance is one of the serious causes of polycystic disease. The reduced response of insulin-sensitive tissues to insulin, despite its sufficient concentration in the body, is called insulin resistance, which leads to chronic compensatory hyperinsulinemia, an important link in the development of increased androgen synthesis.

The combination of high insulin and leptin in the blood

High concentrations of insulin and leptin in the bloodstream against the background of insulin resistance are inherent to many types of obesity and are an element of the metabolic syndrome, which can provoke malignant tumors. Research on the relationship between leptin and reproduction is still sparse, but promising. They confirm that increased insulin and C-peptide secretion and a high index of insulin and leptin resistance associated with obesity increase tumor risk.

Because an eating disorder is the most important trigger of the imbalance between energy intake and energy expenditure. In fact, it is one of the mechanisms for the development of obesity.  To prevent reproductive disorders due to obesity, it is important to achieve a culture of eating behavior, interrupting the very possibility, of disorderly eating.

To summarize

Excess leptin and leptin resistance are the result of obesity with disruption of menses, anovulation, perverted steroid synthesis in the cells of the uterine stroma and appendages. As a result, the hypothalamic-pituitary-ovarian system becomes involved. Leptin resistance eventually can initiate lipotoxic disorders. Adipose tissue hormones, including leptin, serve as a link between obesity and insulin resistance. They become factors that impair sexual and reproductive function in women and provoke cancer.

Prevention of reproductive disorders in obese people consists in instilling normal eating habits in patients, regardless of age.


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