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month for a period of 3 months. With this therapy, there is an increase in testicu-
lar volume by 3–4 ml in 6–9 months, progressive appearance of secondary
sexual characteristics, and acceleration of growth velocity from 4 cm/year to
9–10 cm/year. The increase in testicular volume during testosterone replace-
ment therapy is attributed to increase in FSH secretion by low-dose testoster-
one. The growth spurt which occurs after testosterone therapy is due to gonadal
steroid-mediated increase in GH-IGF1 secretion. Following withdrawal of tes-
tosterone, there is reactivation of HPG axis due to loss of negative feedback at
hypothalamus and pituitary leading to further progression of puberty. If testicu-
lar enlargement does not occur within 3 months after discontinuation of testos-
terone therapy, another short course of testosterone may be administered. If
there is no testicular enlargement even after 1 year of therapy, the diagnosis of
congenital IHH should be considered.- When to induce puberty in boys with congenital IHH?
Puberty should be initiated at a chronological age of 14 years in boys with con-
genital IHH, and this cutoff is based on the definition of delayed puberty. In
addition, boys with congenital IHH with bone age of ≥12 years can also be
considered for pubertal induction.- How to induce puberty in boys with congenital IHH?
Normal puberty is a slow and progressive process which is completed over a
period of 2–5 years; therefore, pubertal development should be accomplished
slowly over a period of 2–5 years. Various treatment modalities used for the
induction of puberty include pulsatile GnRH, hCG with/without FSH, and tes-
tosterone therapy.- What are the merits and demerits of pubertal induction with GnRH in boys with
congenital IHH?
Pulsatile GnRH therapy is the most physiological way to induce puberty and it
results in virilization, testicular growth, and spermatogenesis. GnRH is admin-
istered in a pulsatile manner at an interval of 90–120 min either subcutaneously
or intravenously via a pump. GnRH therapy is effective in nearly 75 % of
patients with congenital IHH. However, this therapy is expensive and
cumbersome. - What are the merits and demerits of pubertal induction with hCG?
Normal pubertal development is orchestrated by synergistic actions of gonado-
tropins. LH acts on Leydig cells and increases the level of circulating testoster-
one, resulting in virilization. LH in concert with FSH initiates the onset of7 Delayed Puberty