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32. What are the hormones responsible for prepubertal penile growth?

During intrauterine period, there is an increase in penile size by approximately

2 cm in second and third trimesters due to the activation of fetal hypothalamic–

pituitary–testicular (HPT) axis. This is mediated by the effects of testosterone

and dihydrotestosterone. During infancy, postnatal surge of testosterone as a

consequence of mini-puberty contributes to penile growth. In addition, growth

hormone also has a permissive role in penile growth during intrauterine and

prepubertal period as evidenced by the presence of micropenis in newborns and

children with growth hormone deficiency.

33. What are the causes of obesity with congenital hypogonadotropic
    hypogonadism?
    Prader–Willi syndrome (PWS) and Laurence–Moon–Bardet–Biedl syndrome
    (LMBB) are characterized by obesity and hypogonadotropic hypogonadism. In
    addition, patients with inactivating mutations of LEP, LEPR, PROK2, and PROKR2
    can also present with obesity and hypogonadotropic hypogonadism (Fig. 7.9).

a b

Fig. 7.8 (a) Micropenis in a patient with hypogonadotropic hypogonadism, (b) buried penis in an
obese boy

7 Delayed Puberty