Luteinizing Hormone-Releasing Hormone (LH-RH, Gonadotropin Releasing Hormone, Gn-RH)

Clinical Significance:
Luteinizing Hormone-Releasing Hormone (LH-RH), also known as Gonadotropin-Releasing Hormone (Gn-RH), is a decapeptide secreted pulsatily from the hypothalamus.  It stimulates the release of the Gonadotropins – Luteinizing Hormone and Follicle Stimulating Hormone – exerting a stronger effect on Luteinizing Hormone.  Testosterone and Estradiol, whose release is stimulated by the Gonadotropins, exert a negative feedback control on LH-RH both at the hypothalamic site and by decreasing pituitary receptor binding.  LH-RH levels are low in patients with hypothalamic hypogonadism differentiating them from the high levels usually found in primary hypopituitary hypogonadism.  Accentuation of the LH-RH pulse occurs at the onset of puberty triggering the release of LH and FSH required in pubertal development.  LH-RH is stimulated by Epinephrine and suppressed by Dopamine and opiates.  LH-RH and some of its agonists are frequently used to induce ovulation.

Reference Range:
Male:                                  4.0 –   8.0 pg/ml
Female:                               2.0 – 10.0 pg/ml

Luteinizing Hormone-Releasing Hormone is measured by direct radioimmuno-assay.

Patient Preparation:
Patient should not be on any Steroid, ACTH, Gonadotropin, or Estrogen medications, if possible, for at least 48 hours prior to collection of specimen.

Specimen Collection:
3 ml serum or EDTA plasma should be collected and separated as soon as possible.  Freeze specimen immediately after separation.  Minimum specimen size is 1 ml.

Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.

Shipping Instructions:
Ship specimens frozen in dry ice.

J Schopohl, G Mehltretter, R von Zumbusch, T Eversmann, and L von Werder.  Comparison of Gonadotropin-Releasing Hormone and Gonadotropin Therapy in Male Patients with Idiopathic Hypogonadism.  Fertility and Sterility 56: 1143-1150, 1991.

2. CB Lambalk, J Schoemaker, GP van Rees, J de Koning, and HAMJ van Dieten.  Exogenous versus Endogenous Pulses of Luteinizing Hormone-Releasing Hormone and Secretory Patterns of Gonadotropins.  Fertility and Sterility 56: 446-452, 1991.