Gonadotropin-releasing Hormone Stimulation
Rationale: This test has been used in the diagnosis of central precocious puberty (CPP) and in the differentiation of CPP from other causes of precocious puberty.1,2 The test has also been used to monitor the effectiveness of gonadotropin-releasing hormone (GnRH) analogue therapy.3 In early childhood, the hypothalamic-pituitary-gonadal axis is inhibited, delaying the onset of reproductive maturity. Puberty occurs as increased secretion of GnRH by the hypothalamus produces an increase in pituitary secretion of gonadotropins. Gonadotropin response, especially that of luteinizing hormone (LH), to exogenous GnRH is markedly enhanced after the onset of puberty. A pubertal response has been defined as an LH level after GnRH stimulation >8 IU/L.2
Protocol: GnRH (100 μg) is administered intravenously. A sample for serum LH should be collected at 40 minutes after GnRH administration.4
Orderable Tests: See Comprehensive List of Procedures section for individual test information.
References
1. Lee PA. Central precocious puberty. An overview of diagnosis, treatment, and outcome. Endocrinol Metab Clin North Am. 1999 Dec; 28(4):901-918. PubMed 10609126
2. Eckert KL, Wilson DM, Bachrach LK, et al. A single-sample, subcutaneous gonadotropin-releasing hormone test for central precocious puberty. Pediatrics. 1996 Apr; 97(4):517-519. PubMed 8632938
3. Lee PA. Laboratory monitoring of children with precocious puberty. Arch Pediatr Adolesc Med. 1994 Apr; 148(4):369-376. PubMed 8148936
4. World Health Organization. Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications. Part 1: Diagnosis and a WHO Consultation. Geneva, Switzerland: WHO;1999. WHO/NCD/NCS/99.2.