Related Experiment Video
Updated: Jul 26, 2025
![Investigating Cardiac Metabolism in the Isolated Perfused Mouse Heart with Hyperpolarized [1-13C]Pyruvate and 13C/31P NMR Spectroscopy](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F63188.jpg&w=3840&q=50)
14:56
Investigating Cardiac Metabolism in the Isolated Perfused Mouse Heart with Hyperpolarized [1-13C]Pyruvate and 13C/31P NMR Spectroscopy
Published on: April 21, 2023
1.5K
3βHSD activity saturates at physiological substrate concentrations in intact cells.
Jeffrey M McManus1, Yoon-Mi Chung1, Nima Sharifi1,2,3,4
1Genitourinary Malignancies Research Center, Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
The Prostate
|June 15, 2023
Summary
Cellular metabolism of dehydroepiandrosterone (DHEA) shows distinct kinetics. Enzyme saturation in prostate cancer cells suggests DHEA concentration fluctuations may be buffered, impacting androgen levels.
Area of Science:
- Biochemistry
- Endocrinology
- Oncology
Background:
- Dehydroepiandrosterone (DHEA) conversion to dihydrotestosterone (DHT) fuels castration-resistant prostate cancer.
- DHEA metabolism involves a branch point with 3β-hydroxysteroid dehydrogenase (3βHSD) and 17βHSD enzymes.
- Understanding these enzymatic kinetics is crucial for prostate cancer research.
Purpose of the Study:
- To investigate the reaction kinetics of DHEA conversion by 3βHSD and 17βHSD in cellular models.
- To elucidate the impact of substrate concentration on these metabolic pathways.
Main Methods:
- Incubation of LNCaP and JEG-3 cells with varying concentrations of DHEA and Δ⁵-androstenediol.
- Measurement of steroid metabolism products using mass spectrometry and high-performance liquid chromatography.
- Kinetic analysis of enzymatic reactions within cellular environments.
Main Results:
- The 3βHSD-catalyzed reaction showed saturation within physiological substrate concentrations.
- Low DHEA concentrations favored 3βHSD conversion to Δ⁴-androstenedione.
- High DHEA concentrations shifted metabolism towards 17βHSD conversion to Δ⁵-androstenediol.
Conclusions:
- Cellular 3βHSD metabolism of DHEA saturates at physiological concentrations, contrary to purified enzyme studies.
- This saturation suggests a buffering mechanism for DHEA fluctuations.
- Potential implications for regulating downstream active androgen levels in prostate cancer.
