Dr. Saoji Orthopaedic Clinic And Medilab Pathology Laboratory
Sky Orthopaedics,1st Floor, Nikalas Tower, Central Bazar Road,Nagpur
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Know About Luteinising Hormone (LH)
Luteinizing hormone (LH) is a hormone associated with reproduction and the stimulation of the release of an egg from the ovary (ovulation) in women and testosterone production in men. This test measures the amount of luteinizing hormone in the blood or urine.
LH is produced by the pituitary gland, a grape-sized organ found at the base of the brain. Control of LH production is a complex system involving the hypothalamus in the brain, the pituitary gland, and the hormones produced by the ovaries and testicles.
In premenopausal women, several hormones rise and fall in a specific sequence during each menstrual cycle. During the cycle, LH stimulates ovulation and the production of other hormones, estradiol and progesterone.
Womens' menstrual cycles are divided into follicular and luteal phases, with each phase lasting about 14 days. Near the end of the follicular phase, there is a mid-cycle surge of follicle-stimulating hormone (FSH) and LH. This surge triggers ovulation, causing the rupture of the egg follicle on the ovary and the release of the egg.
During the luteal phase, the site where the egg follicle ruptured becomes a "corpus luteum." LH secretion stimulates the corpus luteum to start producing progesterone. FSH and LH levels decline, while progesterone and estradiol concentrations increase. These hormone levels decrease in turn after several days if the egg is not fertilized. Menstruation starts and when it ends, the cycle begins again.
As a woman ages and menopause approaches, ovarian function wanes and eventually ceases. As this occurs, FSH and LH levels rise.
In men, LH stimulates Leydig cells in the testicles to produce testosterone. LH levels are relatively constant in men after puberty. A high testosterone level provides negative feedback to the pituitary gland and the hypothalamus, thus decreasing the amount of LH secreted.
In infants and children, LH levels rise shortly after birth and then fall to very low levels (by 6 months in boys and 1-2 years in girls). At about 6-8 years, levels again rise before the beginning of puberty and the development of secondary sexual characteristics.
To evaluate fertility issues, function of reproductive organs (ovaries or testicles), or to detect the release of an egg from the ovary (ovulation); to evaluate pituitary function.In children, to evaluate early or delayed sexual maturation (puberty).For women, when you are having difficulty getting pregnant or are having irregular or heavy menstrual periods; when you are tracking ovulation during your menstrual cycle.
For men, when your partner cannot get pregnant or you have a low sperm count, low muscle mass or decreased sex drive.
When your healthcare provider thinks that you have symptoms of a pituitary disorder or hypothalamic disorder.
When a health practitioner suspects that a child has delayed or earlier than expected sexual maturation.
In adults, LH (and FSH) tests may be ordered when:
A woman is having difficulty getting pregnant or has irregular or an absence of menstrual periods
When it is suspected that a women has entered menopause and her menstrual cycle has stopped or become irregular
When a man's partner cannot get pregnant, when he has a low testosterone level, or when he has low muscle mass or decreased sex drive, for example.
When a health practitioner suspects that a pituitary disorder is present; a pituitary disorder can affect the production of several different hormones so there may be signs and symptoms in addition to infertility that can include fatigue, weakness, unexplained weight loss, and decreased appetite to name a few.
In children, LH and FSH may be ordered when a boy or girl does not appear to be entering puberty at an appropriate age (either too late or too soon). Signs of puberty may include: