L17 - Sex, steroid and NS

Question 1

What enzyme converts testosterone into estradiol?

Answer 1

Aromatase

Question 2

What enzyme converts testosterone into 5 alpha dihydrotestosterone?

Answer 2

5 alpha reductase

Question 3

In males, when does early transient synthesis of testosterone occur?

Answer 3

Pre-birth, second trissmester - causes masulinisation of genitalia

Question 4

Primary source of sex steroids? Minor source?

Answer 4

Gonads, adrenal cortex

Question 5

Are there hormone independent effects?

Answer 5

Yes > 50 genes are expressed at different levels in male vs females BEFORE gonad formation. In gyandromorphs, some brain regions are different on each side

Question 6

How does estrogen act as a critical masculinising factor?

Answer 6

In neurons expressing aromatase, a transient rise in T during develop causes a transient local intracell rise in E. This will initiate changes in neurons that express E receptors

Question 7

Does maternal estrogen affect sexual differentiation of fetal NS?

Answer 7

NO. Fetus expresses high levels of alpha fetoprotein that binds circulating estrogens.

NOTE: Aromatase is located within specific populations of neurons and is intracell, therefore E generated from T are produced within these neurons and protected from alpha fetoprotein

Question 8

Neurogenesis in songbirds

Answer 8

Males sing in breeding season, females do not. Females can learn songs if exposed to androgens early enough.

Question 9

Diseases more prevalent in females

Answer 9

Fibromyalgia, intersitital cystitis/bladder pain syndrome, temperomandibular disorder, migraine

Question 10

Diseases more prevalent in males

Answer 10

Cluster headaches, gout

Question 11

Spinal microglial signalling in pain is different in males and females - drugs blocking microglia are ineffective in pain in females

Answer 11

Spinal microglial signalling in pain is different in males and females - drugs blocking microglia are ineffective in pain in females