Thyroid releasing hormone inhibits testosterone metabolism by rat prostate in vitro

A method involving thin layer chromatography (TLC) was developed to assess 5 alpha-DHT-reductase activity in rat ventral prostate, in terms of the amount of testosterone metabolised to its main 5 alpha-reduced compound, dihydrotestosterone (DHT). Using this method an in vitro study was carried out to determine 5 alpha-DHT reductase activity in the rat ventral prostate as modulated by thyroid releasing hormone (TRH). The study revealed a decrease in the enzyme activity with increasing doses of TRH, as shown by a decrease in the extent of reduction of testosterone to DHT. The ratios of the counts for DHT and testosterone however did not show any dose related effect.