Final answer:
A decrease in DHT and 5-alpha reductase indicates hypoplasia of the testes, which can cause underdevelopment of secondary sexual characteristics, and can be due to primary testicular defects or secondary pituitary gland issues.
Step-by-step explanation:
A decrease in dihydrotestosterone (DHT) and 5-alpha reductase activity can indicate hypoplasia of the testes. DHT is a potent androgen hormone responsible for the development of male characteristics, and it is produced from testosterone by the action of the enzyme 5-alpha reductase. Hypoplasia of the testes leads to a lack of male hormones and could be a result of a primary defect within the testes themselves, or secondary to a defect in the pituitary gland that controls hormone production. This can result in a failure to develop secondary sexual characteristics, lack of masculinization, and atrophy of sex organs later in life. Conditions like hypogonadism that affect testicular function also result in changed hormone levels and might result in down-regulation, which relates to a decrease in the number of hormone receptors in response to increased hormone levels.