Sex steroid transport Flashcards
Describe the daily production rate of testosterone in males.
The daily production rate of testosterone in males is 5-15mg.
What percentage of total testosterone circulates as free biologically active hormone?
2-4% of total testosterone circulates as free biologically active hormone.
What percentage of total testosterone circulates as free biologically active hormone?
2-4% of total testosterone circulates as free biologically active hormone.
What percentage of total testosterone circulates as free biologically active hormone?
2-4% of total testosterone circulates as free biologically active hormone.
What are the two proteins that testosterone binds to?
Testosterone binds to albumin (~38%) and SHBG (~60%).
How does albumin-bound testosterone relate to bioavailability?
Albumin-bound testosterone can also be regarded as ‘bioavailable’ because it is bound to albumin with lower affinity than to SHBG.
What equation is used to estimate free testosterone in men?
The free androgen index ((total testosterone/SHBG) × 100) is of limited value in men.
What is the recommended web-based calculator for estimating free testosterone in men?
The Vermeulen equation is a better validated web-based calculator for estimating free testosterone in men.
What percentage of androstenedione is SHBG-bound?
Only about 6% of androstenedione is SHBG-bound.
Describe the daily production rate of estradiol in females.
The daily production rate of estradiol in females is 40-400 micrograms.
What percentage of free estradiol is biologically active?
2-3% of free estradiol is biologically active; the rest is bound to SHBG.
