transport

Last reviewed 01/2018

98-99% of sex steroids are transported haematogenously by combination with protein. This is required because:

• steroids are relatively insoluble in plasma
• it minimizes filtrative losses by the kidney

The contribution of individual proteins is dependent on the particular sex steroid subclass:

• oestradiol: 48% bound to albumin; 51% bound to specific binding globulin
• progesterone: 48% bound to albumin; 50% bound to specific binding globulin
• androgen: 40% bound to albumin; 58% bound to specific binding globulin