Sex hormone testing has important clinical significance in andrology.

The health of men's private parts requires not only daily care, but regular examinations are also an important preventive measure. So what is the significance of sex hormone testing for men in life?

1. Serum follicle stimulating hormone (FSH) and luteinizing hormone (LH)

What are FSH and LH?

The synthesis and secretion of serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) are mainly regulated by gonadotropin-releasing hormone (GnRH). GnRH promotes the secretion of FSH and LH. The latter is released synchronously with the frequency of the former. It is also regulated by the negative feedback of testosterone (T) and estradiol (E2). They are very important endocrine hormones. In men, FSH mainly acts on spermatogenic and supporting cells of the testicles, and LH mainly acts on interstitial cells of the testicles. Therefore, the two have very important physiological effects.

2. Serum testosterone (T)

What is T?

Testosterone (T) is mainly secreted by testicular interstitial cells. Only about 2% of testosterone in plasma exists in free form. Testosterone in this form is biologically active, and the vast majority of the rest is bound to plasma proteins. Testosterone has very important physiological effects, such as inducing embryos containing Y chromosomes to differentiate into males, promoting the development of internal reproductive organs, maintaining spermatogenesis, stimulating the growth of accessory organs and maintaining sexual desire, and promoting protein synthesis, especially in muscles and reproductive organs, and bone growth.

3. Serum PRL and Estradiol (E2)

What are PRL and E2?

Pituitary prolactin (PRL) is a protein hormone secreted by the pituitary gland, so it can indirectly reflect the function of the pituitary gland. PRL mainly acts on the breast, and works synergistically with estrogen and progesterone to promote the development of the breast. Estradiol (E2) is the most important estrogen, which can promote and regulate the normal development of female sexual organs and secondary sexual characteristics.

Why do these tests?

The examination of sex hormones is a very important component of men's examination. Their increase or decrease has very important clinical significance. FSH in the male body mainly acts on the spermatogenic and supporting cells of the testicles, and LH mainly acts on the interstitial cells of the testicles. When the basal levels of LH and FSH are significantly increased, it indicates testicular failure; when the basal levels of FSH and LH are reduced or are at the lower limit of normal, the lesions of patients with testicular dysfunction may be in the hypothalamus or pituitary gland, which is secondary testicular dysfunction, which is also one of the manifestations of hypogonadotropic hypogonadism (HH).

For example, if the PRL level is significantly elevated, FSH and LH are low or at the lower limit of normal, and accompanied by sexual dysfunction, oligospermia, ED, etc., it may be hyperprolactinemia, lactoma, or pituitary microadenoma. If the PRL level is >200ug/L, the presence of a pituitary tumor is almost certain.

When T value is analyzed in conjunction with other hormones, it also has very important clinical significance. For example, when FSH and LH are elevated, T or T/LH ratio decreases, which is a typical manifestation of hypergonadotropic hypogonadism, indicating primary testicular failure, such as Klinefelter syndrome, severe varicocele, etc.

A decrease in T level or an increase in E2 level, or a decrease in the T/E2 ratio, can be seen in testicular dysfunction caused by various reasons.