Name of the Test:   Gonadotropin Releasing Hormone (Gn RH )

Alias Names:  LH RH (luteinizing hormone releasing hormone), Gn-RH.

Gn RH determination is useful   ,

– In the assessment of reproductive disorders

– To determine the concentration of Gn RH following  stimulation to induce ovulation

In the diagnosis of hypopituitary hypogonadism ( secondary hypogonadism )  

Clinical Applications :

Gonadotropin releasing hormone (Gn RH or LH RH) is a ten amino acid peptide produced mainly in the hypothalamus. It stimulates pituitary for the production of LH and FSH. The stimulation is predominantly on LH secretion and hence it is called LH RH. LH and FSH stimulates the production of gonadal hormones (e.g) testosterone in males and estrogens in females. These steroid hormones have a feedback control on Gn RH secretion. Increased secretion occurs during puberty leading to the raise in concentration of LH and FSH for the stimulation of gonads. LH RH levels are high when there is secondary hypogonadism with decreased level of LH and FSH. LH RH levels are low in tertiary(hypothalamic) hypogonadism and also individuals with high stress levels with elevated dopamine and prolactin. LH RH and its agonists are routinely used in IVF settings to induce ovulation.

Method:

Samples are routinely extracted to eliminate matrix effect and inteferences. The extracted samples are assayed using a competitive immunoassay with a sensitive anti-Gn RH and biotinylated Gn RH. The assay is specific for Gn RH and less than 1 % crossreactivity with other hypothalamic peptides.

Test request information :

Specimen requirements: 3.0 ml (minimum 0.7 ml) of  EDTA plasma . Serum is acceptable if they are collected and stored frozen immediately.

Patient Preparation: Patients should not be on any hormonal treatment for 2 days.

Shipping requirements: Store the sample frozen. Ship the samples frozen in Dry ice.

Turnaround time: 1 week (Set up every Tuesday and reported the following day ).Repeat samples are assayed the same week.

Reference Range (Adults):    Less than 10 pg /ml

References:

  1. Conn PM and Crowley WF Jr (1994)  Gn RH and its aanalogs . Ann review of Medicine 45: 391 – 405.
  2. Limonta P, Moretti RM, Marelli MM, Motta M (2004) The biology of gonadotropin -releasing hormone: role in the control of tumor growth and progression in humans. Frontiers in neuroendocrinology 24: 279–95.
  3. Yen SS (1983) Clinical applications of gonadotropin-releasing hormone and gonadotropin-releasing hormone analogs. Fertil Steril  39: 257-66.

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