July 27, 2017
hCG Stimulation Test Minimize

hCG Stimulation Test

Indication

  • In the infant with ambiguous genitalia and palpable gonads
  • In male delayed puberty and/or undescended testes
  • To confirm the presence of active testicular tissue

Male newborn infants usually have plasma testosterone concentrations within the low adult range (8-12 nmol/L) and both LH and testosterone are at adult values during the third and fourth months. If blood can be obtained during these times, an hCG test may be avoided.

Contraindication

Principle

hCG is a double polypeptide hormone and shares a common subunit with LH. It stimulates testicular Leydig cells to secrete androgens via the LH receptors. A single injection of hCG is adequate as it has a long half life (2.5 days) and produces a progressive but modest rise in plasma testosterone for 72-120 hours.

Side effects

Headaches, tiredness.

Preparation

No patient preparation is required

Requirements

  1. 1 vial hCG 1500 units for infants or 5000 units for children over 2 years
  2. 2 serum tubes

Procedure

  1. day 0: take blood for testosterone, androstenedione and dihydrotestosterone
  2. administer 1500 units (infants) or 5000 units (over 2 years) hCG subcutaneously or im
  3. day 4: take blood for testosterone, androstenedione and dihydrotestosterone

Interpretation

 

 testosterone

 DHT

 T/DHT ratio after hCG

 Normal male adults

 8-27 nmol/L

 < 2.9 nmol/L

 <12

 Normal children (6 months - puberty)

 < 0.9 nmol/L

 < 0.1 nmol/L

 <12

 5α-reductase (6 months - puberty)

 < 0.5 nmol/L

 

 >12

  1. There is a 2-9 fold increase in testosterone in normal prepubertal boys. In the absence of testes, no response in testosterone occurs.
  2. Normal males show a complex pattern of testosterone. In the first week there is a mdestly elevated testosterone concentration due to gonadal stimulation by maternal hCG. During a period with months 2-6 of age, testosterone should reach tyhe lower end of the adult range associated with adult gonadotrophins (LH>FSH). Therefafter testosterone become undetectable until the onset of puberty.
  3. There are reported errors in the interpretation of the hCG stimulation test in boys of approx 8 years with increased T:DHT ratios in the 5α-reductase range.

References

  • Chaussain JC, Gendrel D, Roger M, Boudailleiz B, Job JC. Longitudinal study of plasma testosterone in male pseudohermaphroditism during early infancy. J Clin Endocrinol Metab 1979;49:305-306.
  • Forrest MG, Cathiard AM. Patterns of plasma testosterone and androstenedione in normal new-borns: evidence for testicular activity at birth. J Clin Endocrinol Metab 1975;41:977-980.
  • Forest MG, David M, Lecoq A, Jeune M, Bertrans J. Kinetics of the hCG-induced steroidogenic response of the human testis. III. studies in children of the plasma levels of testosterone and hCG: rationale for testicular stimulation test. Pediatr Res 1980;14:819-824.
  • Grant DB, Lawrence BM, Atherden SM, Ryness J. hCG stimulation test in children with abnormal sexual development. Arch Dis Childh 1976;51:596-601.
  • Maimoun L et al. Phenotypical, biological,a nd molecular heterogeneity of 5α-reductase deficiency: an extensive international experience of 55 patients. J Clin Endocrinol Metab 2011;96:296-307.
  • Saez JM, Forest MG. Kinetics of human chorionic gonadotropin-induced steroidogenic response of the human testis. 1. plasma testosterone: implications for human chorionic gonadotropin stimulation test. J Clin Endocrinol Metab 1979;49:278-283.
  • Toscano V, Balducci R, Adama MV, Manca Bitti ML, Sciarra F, Boscherini B. Response to a single dose of human chorionic gonadotropin in prepubertal boys. Clin Endocrinol (Oxf) 1983;57:421-424.

JHB 17 Oct 2011

  

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