Luteinizing hormone stimulates the testes in males and the ovaries in females. This hormone is vital for reproductive health.

What is Luteinizing Hormone?

Luteinizing hormone (LH) a hormone released by the pituitary gland in response to luteinizing hormone-releasing hormone (LHRH) (R). LHRH is released from the hypothalamus.

LH is a gonadotropic hormone and controls the functions of the female ovaries and male testes. It is also essential for proper reproductive function.

In males, it is also called the Interstitial cell stimulating hormone (ICSH) (R).

In general, when estrogen and progesterone levels fall, LH levels rise. Follicle Stimulating Hormone (FSH) is synergistic with LH.

In Women

In women, luteinizing hormone (LH) carries out different roles in the two halves of the menstrual cycle.

In weeks 1 – 2 of the cycle, LH is required to stimulate the ovarian follicles in the ovary to produce the female sex hormone, estradiol.

Later a surge in LH levels causes Ovulation. In the remainder of the cycle, LH stimulates the corpus luteum to produce progesterone which is required to support the early stages of pregnancy, if fertilization occurs (R).

In Men

Luteinizing hormone stimulates Leydig cells in the testes to produce testosterone. If testosterone levels decrease, LH secretion increases. This is known as negative feedback.

Testosterone, in turn, stimulates sperm production as well as generating male characteristics throughout the body (R).

Reduced LH Levels

Low levels of LH will limit sperm production and can cause infertility.

Kallmann’s syndrome is caused by a deficiency in gonadotropin-releasing hormone (i.e., LHRH). It can result in a lack of sexual development, a small penis, undeveloped testes, and a delay in or lack of puberty (R).

In women, low levels of luteinizing hormone can lead to low levels of estrogen and improper development of corpora lutea (R).

Negative Associations With Abnormal Luteinizing Hormone


A major depressive disorder is associated with abnormal regulation of LH (R).


In postmenopausal women, an increase in LH levels can lead to Alzheimer’s Disease development. LH has been shown to promote the deposition of amyloid β plaques in the hippocampus (R).


Women with an LH level greater than one standard deviation above the average have a decrease in the rate of fertilization (R).

Patients with Polycystic Ovary Syndrome (POS) have a high pulsatile level of LH (R).

Klinefelter’s syndrome

High LH levels are seen in genetic conditions such as Klinefelter’s syndrome. Klinefelter’s syndrome shrinks your testes and causes them to not produce enough testosterone for sperm production (R).

Luteinizing Hormone (LH) Test

An LH test measures the amount of Luteinizing Hormone in the sample of blood or urine. It may be done to find the cause of a couple’s inability to become pregnant. LH test is commonly used to evaluate:

  • A woman’s egg supply (ovarian reserve)
  • A man’s sperm count
  • menstrual problems in women.
  • a women’s response to medicines taken to stimulate ovulation.

Irregular Luteinizing Hormone Levels?

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