GnRH

(noun)

Gonadotropin-releasing hormone is a trophic peptide hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary.

Related Terms

Examples of GnRH in the following topics:

  • Hormonal Regulation of the Reproductive System

    • Male and female gonads are regulated by FSH and LH from the pituitary; their production is stimulated by GnRH, secreted by the hypothalamus.
    • An increase in gonad hormone levels inhibits GnRH production through a negative feedback loop .
    • At the pituitary, GnRH stimulates the synthesis and secretion of the gonadotropins, FSH and LH.
    • Low-frequency GnRH pulses lead to FSH release, whereas high-frequency GnRH pulses stimulate LH release.
    • GnRH, secreted by the hypothalamus, stimulates the production of FSH and LH from the pituitary gland.

  • Male Hormones

    • At the onset of puberty, the hypothalamus begins secreting high pulses of GnRH, or gonadotropin-releasing hormone.
    • A negative feedback system occurs in the male with rising levels of testosterone acting on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH .
    • This inhibits the release of GnRH and FSH, which will cause spermatogenesis to slow down.
    • GnRH stimulates the production of FSH and LH, which act on the testes to begin spermatogenesis and to develop secondary sex characteristics in the male.
    • In turn, the testes production of testosterone and the hormone inhibin inhibit the release of GnRH, FSH, and LH in a negative feedback loop.

  • Hormonal Regulation of the Male Reproductive System

    • Gonadotropin-releasing hormone (GnRH) is mainly made in the preoptic area of the hypothalamus before traveling to the pituitary gland.

  • Female Hormones

    • As with the male, the hypothalamic hormone GnRH (gonadotropin-releasing hormone) causes the release of the hormones FSH (follicle stimulating hormone) and LH (luteinizing hormone) from the anterior pituitary.
    • The decrease in progesterone also allows the hypothalamus to send GnRH to the anterior pituitary, releasing FSH and LH to start the cycles again .

  • Organs with Secondary Endocrine Functions

    • It must be present for GnRH and gonadotropin synthesis to occur.

  • Hormonal Methods

    • Progesterone negative feedback decreases the frequency of gonadotropin-releasing hormone (GnRH) released by the hypothalamus, which decreases the release of follicle-stimulating hormone (FSH), and greatly decreases the release of luteinizing hormone (LH) by the anterior pituitary.

  • Puberty

    • GnRH signals from the hypothalamus induce pulsed secretion of LH (and to a lesser degree, FSH) at roughly one to two hour intervals.

  • Hormonal Regulation of the Female Reproductive Cycle

    • This increased level of estrogen stimulates production of gonadotropin-releasing hormone (GnRH), which increases production of LH.

  • Erythroblastosis Fetalis (Hemolytic Disease of the Newborn)

    • In the past, a woman who was Rh- and who mated with a man who was Rh+ would have difficulty bearing healthy infants who would survive.
    • However, since the 1960s and the development of RhIG, Rh- women who have received this pre-partum treatment have been able to bear healthy infants.
    • In other words, if a mother has anti-RhD (D being the major Rhesus antigen) IgG antibodies as a result of previously carrying a RhD-positive fetus, this antibody will only affect a fetus with RhD-positive blood.
    • Rhesus-negative mothers who have had a pregnancy with/are pregnant with a rhesus-positive infant are given Rh immune globulin (RhIG) at 28 weeks and 34 weeks during pregnancy, and within 72 hours after delivery to prevent sensitization to the D antigen.
    • A drawback to pre-partum administration of RhIG is that it causes a positive antibody screen when the mother is tested, which can be difficult to distinguish from natural immunonological responses that result in antibody production.

  • Independence

    • 2.31: The abbreviations RH and LH are used for right-handed and left-handed, respectively.
    • Since each are independent, we apply the Multiplication Rule for independent processes: P(all five are RH) = P( first = RH, second = RH, ..., fth = RH) = P( first = RH) x P(second = RH) x...x P( fth = RH) = 0.91 x 0.91 x 0.91 x 0.91 x 0.91 = 0.624 (b) Using the same reasoning as in (a), 0.09 x 0.09 x 0.09 x 0.09 x 0.09 = 0.0000059 (c) Use the complement, P(all five are RH), to answer this question: P(not all RH) = 1 - P(all RH) = 1 - 0:624 = 0:376