Glutathione S-transferase in humans: development and tissue distribution

Area of Science:

• Biochemistry
• Developmental Biology
• Toxicology

Background:

• Glutathione S-transferases (GSTs) are crucial enzymes involved in detoxification.
• Understanding GST development and activity across human tissues is vital for assessing toxicological risk.
• Benzo(a)pyrene-4,5-oxide (BPO) is a model substrate for studying GST activity.

Purpose of the Study:

• To quantify and compare Glutathione S-transferase (GST) activity in fetal and adult human tissues.
• To investigate the developmental profile of GST activity during mid-gestation.
• To examine the relationship between GST activity and age in adult organs.

Main Methods:

• GST activity was measured using benzo(a)pyrene-4,5-oxide (BPO) as a substrate.
• Tissue specimens were collected from fetal and adult livers, placentas, lungs, kidneys, and gut.
• Enzyme activity was quantified in cytosolic fractions.

Main Results:

• Fetal liver GST activity was approximately two-thirds of adult liver activity.
• Fetal non-hepatic tissues (lungs, kidneys, gut) showed similar or higher GST activity compared to adult counterparts.
• GST activity in fetal liver and placenta did not correlate with gestational age (11-25 weeks).
• GST activity in adult liver did not correlate with age (32-70 years).

Conclusions:

• GST activity is present before the 11th week of gestation and is stable during mid-gestation.
• Fetal non-hepatic tissues exhibit robust GST activity, suggesting significant detoxification capacity early in development.
• These findings highlight the developmental expression of detoxification enzymes and their implications for xenobiotic metabolism.