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June 25th, 2019
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MEDICA 2019 - World Forum for Medicine
Düsseldorf, GermanyBooth No.: 3/D35-2
AACC Annual Scientific Meeting and Clinical Lab Expo
Anaheim Convention Center ~ Anaheim, CABooth No.: 2627
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The DRG LH (Urine) ELISA is an enzyme immunoassay for the quantitative in vitro diagnostic
measurement of LH in urine. This test is used to detect the midcycle LH surge in urine, which is an aid in predicting the time of ovulation.
Luteinizing hormone (LH) is produced in both men and women from the anterior pituitary gland in response to luteinizing hormone-releasing hormone (LH-RH or Gn-RH), which is released by the hypothalamus (1-3). LH, also called interstitial cell-stimulating hormone (ICSH) in men, is a glycoprotein with a molecular weight of approximately 30.000 daltons (4). It is composed of two non covalently associated dissimilar amino acid chains, alpha and beta (5).
The alpha chain is similar to that found in human thyroid-stimulating hormone (TSH), follicle stimulating hormone (FSH), and human chorionic gonadotropin (hCG). The difference between
these hormones lie in the amino acid composition of their beta subunits, which account for their immunological differentiation (6-8).
The basal secretion of LH in men is episodic and has the primary function of stimulating the interstitial cells (Leydig cells) to produce testosterone. The variation in LH concentrations in women is subject to the complex ovulatory cycle of healthy menstruating women, and depends upon a sequence of hormonal events along the gonado-hypothalamic-pituitary axis. The decrease in progesterone and estradiol levels from the preceeding ovulation initiates each menstrual cycle (9,10). As a result of the decrease in hormone levels, the hypothalamus increases the secretion of gonadotropin-releasing factors (GnRF), which in turn stimulates the pituitary to increase FSH production and secretion (4). The rising FSH levels stimulate several follicles during the
follicular phase, one of these will mature to contain the egg.
As the follicle develops, estradiol is secreted, slowly at first, but by day 12 or 13 of a normal cycle increasing rapidly. LH is released as a result of this rapid estradiol rise because of direct stimulation of the pituitary and increasing GnRF and FSH levels. These events constitute the pre-ovulatory phase (11). Ovulation occurs approximately 12 to 18 hours after the LH reaches a maximum level. After the egg is released, corpus luteum is formed which secretes progesterone and estrogen - two feedback regulators of LH (3,10).
The luteal phase rapidly follows this ovulatory phase, and is characterized by high progesterone levels, a second estradiol increase, and low LH and FSH levels (12). Low LH and FSH levels are the result of the negative feedback effects of estradiol and progesterone on the hypotalamic-pituitary axis. After conception, the developing embryo produces hCG, which causes the corpus luteum to continue producing progesterone and estradiol. The corpus luteum regresses if pregnancy does not occur, and the corresponding drop in progesterone and estradiol levels results in menstruation. The hypothalamus initiates the menstrual cycle again as a result of these low hormone levels (12).
Patients suffering from hypogonadism show increased concentrations of serum LH. A decrease in steroid hormone production in females is a result of immature ovaries, primary ovarian failure, polycystic ovary disease, or menopause; in these cases, LH secretion is not regulated (10,13). A similar loss of regulatory hormones occurs in males when the testes develop abnormally or anorchia exists. High concentrations of LH.