Citrate in plasma and urine during total fasting

Area of Science:

• Biochemistry
• Human Physiology
• Metabolic Studies

Background:

• Obesity is a complex metabolic condition.
• Fasting is a dietary intervention with significant metabolic effects.
• Citrate plays a role in cellular metabolism and energy regulation.

Purpose of the Study:

• To investigate the impact of total fasting on plasma citrate levels and urinary citrate excretion in obese subjects.
• To assess the relationship between plasma citrate concentration and glucose metabolism during fasting.

Main Methods:

• 12 obese subjects underwent a 10-day total fasting period.
• Plasma citrate concentrations were measured before and on the 10th day of fasting.
• 24-hour urinary citrate excretion was monitored in six subjects.
• Intravenous glucose tolerance tests (IVGTT) were performed before and after fasting.

Main Results:

• Mean plasma citrate concentration significantly increased from 128 to 205 micro mol/L after 10 days of fasting.
• Plasma citrate levels showed a continuous rise during the fasting period.
• Urinary citrate excretion decreased significantly from 2.91 to 0.25 mmol/24 h.
• The intravenous glucose tolerance test (Kivgtt) decreased significantly and was inversely related to plasma citrate levels.

Conclusions:

• Total fasting leads to a significant increase in plasma citrate concentration in obese individuals.
• Fasting markedly reduces urinary citrate excretion.
• Elevated tissue citrate levels may play a regulatory role in decreased glucose utilization during fasting in humans.