Gnadotropin releasing hormone agonist (triptorelin)‎ test to differentiate gonadotropin deficiency from constitutionally delayed puberty

Abstract EN

-The objective of this study was to determine whether the hormonal response to GnRH agonist (triptorelin) can differentiate hypogonadotropic hypogonadism (HH) from constitutional delayed puberty (CDP).

The study was carried on 18 boys with CDP ranging in age from 14-19.2 years (15.2±1.4yr), and 10 boys with HH ranging in age from 14-25 years (17.84±3.0yr).

Seven normal prepubertal boys (Tanner 1) and 8 normal early pubertal boys (Tanner 2) were studied as controls.

All boys with CDP entered into puberty spontaneously during follow-up.

Nine HH boys had thalassemia major and 1 boy had Kallmann syndrome.

Each patient had a triptorelin test with measurement of FSH, LH and testosterone before and 4hr following the subcutaneous administration of triptorelin in a dose of 0.1 mg/m2 (max 100 microgram).

CDP and HH patients could not be distinguished by pubertal staging criteria.

HH patients had LH levels of less than or equal to 8.0 mlU/ml 4h post triptorelin.

In all but 4 boys in the CDP group, LH level at this time was greater than 8.0 mlU/ml.

There was a marked overlap in peak FSH and testosterone levels between both groups.

The ratio of the percent change in LH and FSH (a% LH/a% FSH) at 4 hr below 3.8 was the best discriminator, it distinguished HH from CDP in 93% of cases.

Testosterone levels 4hr post-triptorelin are not reliable for distinguishing CDP from HH.

In Conclusion, the triptorelin test appears to be reliable, relatively inexpensive and well tolerated.