Serum bioavailability of sex steroid hormones.

Article Details

Citation

Pardridge WM

Serum bioavailability of sex steroid hormones.

Clin Endocrinol Metab. 1986 May;15(2):259-78.

PubMed ID
3521955 [ View in PubMed
]
Abstract

This chapter has reviewed the factors underlying the transport of testosterone and oestradiol into tissues in vivo. The following points have been emphasized. Albumin-bound testosterone is nearly freely available for transport into brain and liver and is partially available for transport into salivary gland and lymph node; testosterone transport into hair follicles has not been measured thus far. SHBG-bound testosterone is not available for transport into tissues; SHBG-bound oestradiol is available for transport into liver, salivary gland, and lymph node, bug not into brain under normal conditions. The transport of hormone from the circulating plasma protein-bound pool involves tissue-mediated enhanced dissociation of the hormone from the protein without significant exodus of the plasma protein from the microcirculation compartment. The tissue-mediated enhanced dissociation mechanism varies in activity between different organs and is a much more important factor than organ differences in capillary transit times in regulating the amplification of hormone delivery to different tissues. The concentration of free testosterone inside cells in the absence of significant cellular metabolism of the hormone is nearly ten times greater than the concentration of free testosterone in vitro, but is nearly equal to the concentration of free plus albumin-bound hormone. In the presence of active tissue metabolism of hormone, the concentration of cellular free testosterone may be much less than the albumin-bound hormone and may fortuitously approximate the concentration of free testosterone in vitro. This is the situation in salivary gland; the low concentration of testosterone in saliva appears to be due to active salivary metabolism of the hormone, since both free and albumin-bound testosterone are available for transport into salivary gland.

DrugBank Data that Cites this Article

Drug Carriers
DrugCarrierKindOrganismPharmacological ActionActions
EstradiolSex hormone-binding globulinProteinHumans
Unknown
Binder
Details
Estradiol acetateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
Estradiol benzoateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
Estradiol cypionateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
Estradiol dienanthateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
Estradiol valerateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
Estrone sulfateSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
MethyltestosteroneSerum albuminProteinHumans
Unknown
Not AvailableDetails
MethyltestosteroneSex hormone-binding globulinProteinHumans
Unknown
Not AvailableDetails
TestosteroneSerum albuminProteinHumans
No
Binder
Details
TestosteroneSex hormone-binding globulinProteinHumans
No
Binder
Details
Testosterone cypionateSerum albuminProteinHumans
No
Other/unknown
Details
Testosterone cypionateSex hormone-binding globulinProteinHumans
No
Other/unknown
Details
Testosterone enanthateSerum albuminProteinHumans
No
Other/unknown
Details
Testosterone enanthateSex hormone-binding globulinProteinHumans
No
Other/unknown
Details
Testosterone undecanoateSerum albuminProteinHumans
No
Other/unknown
Details
Testosterone undecanoateSex hormone-binding globulinProteinHumans
No
Other/unknown
Details