This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Gonadal Hormones-Androgens – Set 2”.
1. How do free testosterone enters the target cells?
a) By simple/facilitated diffusion
b) By ABC transporters
c) By Voltage gated pump
d) By Ligand gated channels
View Answer
Explanation: Free testosterone, by simple diffusion or facilitated diffusion, reaches the target cells. Testosterone is converted into the ‘active’ form of dihydrotestosterone in the cytoplasm of target cells. Free testosterone is also referred to as bioavailable testosterone, along with albumin-bound testosterone.
2. What are the androgens secreted in the urine are collectively known as?
a) 18-ketosteroids
b) 17-ketosteroids
c) 21-ketosteroids
d) 15-oxosteroids
View Answer
Explanation: The urine-excreted androgens are known as 17-ketosteroids. It provides an idea of the state of the adrenal cortex and its roles in the case of females. 17-ketosteroids are compounds that develop when male steroid sex hormones called androgens and other hormones are produced in males and females by the adrenal glands.
3. Where is the major portion of 17-ketosteroids produced in males?
a) Penis
b) Urethra
c) Adrenal cortex
d) Liver
View Answer
Explanation: 17-ketosteroids (1/3 of the total) come from the testes in males. Although the greatest quantity comes from the adrenal cortex (2/3/3). They are also produced from the adrenal cortex in females as well.
4. Approximately 0.4 mg of testosterone is reduced daily to ‘dihydrotestosterone’ (DHT).
a) True
b) False
View Answer
Explanation: 0.4 mg of testosterone in testes and extra testicular tissues is reduced daily to ‘dihydrotestosterone’ (DHT). DHT is the active form of testosterone that is produced in testes and extra testicular tissues.
5. There is a small amount of testosterone in females.
a) True
b) False
View Answer
Explanation: In females also, there is a small amount of testosterone. This is formed as a result of ovary’s peripheral conversion of androstenedione to testosterone. Testosterone plays a part in the development and maintenance of female reproductive tissue and bone mass, alongside the female sex hormone oestrogen.
6. What is the normal urine level of 17-ketosteroids in males?
a) 10 to 25 mg
b) 9 to 24 mg
c) 18 to 25 mg
d) 9 to 30 mg
View Answer
Explanation: The major portion of this hormone arises from the adrenal cortex. Normal adult males excrete 9 to 24 mg of neutral 17-ketosteroids within 24 hours. Due to adrenarche, adrenal 17-ketosteroid secretion progressively starts during mid-childhood.
7. What is the normal urine level of 17-ketosteroids in females?
a) 5 to 17 mg
b) 10 to 25 mg
c) 18 to 25 mg
d) 9 to 30 mg
View Answer
Explanation: Normal adult females excrete 5 to 17 mg of neutral 17-ketosteroids within 24 hours of urinary excretion. The 17-ketosteroids are almost exclusively produced from adrenal cortex in females. Deficiency of 17-ketosteroid reductase in the testes leads to an inability of androstenedione to synthesise testosterone.
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