Male Puberty

Question 1

Which cells in the testicle may be stimulated by hCG?

Answer 1

Leydig cells (this may be significant in cases of choriocarcinoma, seminomas, and teratomas)

Question 2

At what time point are all testicular components present in a fetus?

Answer 2

11 weeks (this is when levels of testosterone secreted by Leydig cells are peaking)

Question 3

At what week do the testes descend to the inguinal ring?

• what hormone mediates this effect?

Answer 3

Testes descend to the inguinal ring around 14 weeks this is mediated by INL3

Question 4

Babies born before _________ weeks may have testes found in the inguinal ring. This means ___________ has not has time to mediate the full descent.

Answer 4

35 weeks

Testosterone

Question 5

What gonadotropin is most elevated during the mini-puberty?
• what cells are stimulated?
• what is secreted by these cells?

Answer 5

FSH mediates the mini-puberty leading to sertoli cell stimulation that then secrete INHIBIN B
INHIBIN B levels are elevated between 3 months and 1 year

Question 6

When do GnRH levels reach their nadir?

Answer 6

6 years old

they are overall at a minimum between 1 and 6 years of age

Question 7

What factors are important in maintenance of the gonadostat in the prepuberty stage?

Answer 7

• GnRH
• NPY
• GABA
• Leptin
• TGF-alpha

Question 8

What is the earliest stage of male puberty?

• what marker in the blood would indicate this?

Answer 8

Adrenarche - 1st earliest change in male puberty

DHEA-S levels become elevated

Question 9

What hormones reach their maximal levels during puberty leading to increased secretion of gonadotropins?

Answer 9

Kiss peptin

GPR54

Question 10

Which gonadotropin is the primary driver of male (and female) puberty?

Answer 10

LH

Recall that FSH is very important in the mini-puberty

Question 11

What is the most important determinant of when male puberty will take place?

Answer 11

Genetic Factors

Question 12

What is the 1st PHYSICAL sign of male puberty?

Answer 12

Testicles at 4mm suggests onset of puberty

Question 13

What defines a constitutional delay of puberty in males?

Answer 13

2-3 years delay in the onset of puberty in males = constitutional delay

**More common in males than females

Question 14

At what age does adrenarche typically occur in a male?

• what part of the adrenal gets developed?

Answer 14

9 years old
**From development of the Zona Reticularis

**Increased 17(OH) pregnenolone and DHEA relative to cortisole will be present

Question 15

Give the 5 tanner stages of the male genitalia.

• what age do these typically occur?

Answer 15

1. 9 yrs - testes less than 2.5cm (less than 4cc) - Adrenarche
2. 12 yrs - Thinning and Reddining of the Scrotum testes (2.5-3.5 cm) - onset of puberty
3. 13 yrs - growth of the penis and testes
4. 14 yrs - Growth of the penis and GLANS and darkening of scrotum
5. 15 yrs - Adult genitalia

Question 16

Give the 5 tanner stages of male Pubic hair?

• what age do these typically occur?

Answer 16

1. Villus hair only - 9 yrs
2. Sparse dark hair - 12 yrs - puberty
3. Thicker hair to mons - 13 yrs
4. Adult type, no thigh involement - 14 yrs
5. Spread to thighs - 15 yrs

Question 17

At what tanner stage is the maximal growth rate achieved?

Answer 17

Tanner 4 corresponds to a growth rate of about 10 cm/yr

Question 18

Note: you can have BO and Body hair in a young male but if genitalia is not enlarged then there is not a need to worry about precocious puberty

Answer 18

Note: you can have BO and Body hair in a young male but if genitalia is not enlarged then there is not a need to worry about precocious puberty