Zinc concentration and progestin receptor in human benign hyperplastic prostate

Area of Science:

• Endocrinology
• Molecular Biology
• Oncology

Background:

• Benign prostatic hyperplasia (BPH) is a common condition in aging men.
• Progestin receptors play a role in prostate tissue function and disease.
• The influence of cations like zinc on hormone receptor binding in BPH is not fully understood.

Purpose of the Study:

• To investigate the effect of cationic zinc on the specific binding of promegestone (R5020) to its receptor in human benign hyperplastic prostate cytosols.
• To determine if endogenous or added zinc influences progestin receptor levels.

Main Methods:

• Analysis of zinc concentration using flameless atomic absorption spectrometry.
• Assay of progestin specific binding via sucrose density gradient centrifugation.
• Investigation of zinc's effect by adding excess zinc, removing zinc via gel filtration, and using chelating agents.

Main Results:

• Endogenous zinc levels in BPH cytosols ranged from 0.15 mM to 0.88 mM.
• No significant relationship was found between zinc concentration and progestin specific binding.
• Addition or removal of zinc did not alter the amount of 7-8S progestin specific binding.

Conclusions:

• Cationic zinc, at concentrations up to 2 mM, does not affect the specific binding of progestin receptors in BPH cytosols.
• The observed inhibition by EDTA was likely due to its anionic properties, not chelation.
• Zinc does not appear to modulate progestin receptor availability in this tissue.