Lactate is formed naturally in the body in example during physical activity. However, lactate
is also formed during food fermentation where certain bacterial strains form lactate. Lactate
can also be produced chemically. An example of this is Ringer-lactate which is used for
volume replacement when treating dehydrated patients.
As a source of carbon-molecules, lactate is believed to be an important oxidative fuel source
in all major organs and yields adenosine triphosphate (ATP) production through Krebs cycle,
the Electron Transport Chain in the mitochondria as well as by being a key precursor for
gluconeogenesis.
Metformin is the first drug of choice for type 2 diabetes treatment. Use of metformin often
results in a small but significant weight loss in overweight users. It is known that
metformin increases the lactate concentration in the gut. It is also known also know that
metformin use is associated with an increase in blood concentrations of growth
differentiation factor 15 (GDF-15). Receptors for GDF-15 can be found in parts of the brain
associated with control of appetite. In rats increases in [GDF-15] results in a decrease in
appetite and thus weight loss. GDF-15 is thought to be involved in the normal energy
homeostasis.
With this study the investigators want to examine the hormonal, metabolic and mechanical
effects of lactate in the gut in healthy volunteers. Our hypothesis is that lactate has
beneficial effects which may be though an increase in GDF-15 in the blood.
Volunteers will undergo two study days separated by at least 7 days and a maximum of 1 month.
- On day one volunteers will drink a sodium-lactate solution (intervention). The
investigators will also administrate 1500mg paracetamol to assess gastric emptying and
do blood samples over 4 hours. The investigators measure [lactate] every 15 min. Every
hour the investigators will ask volunteers questions regarding hunger and thoughts of
future food intake (questionnaire). After 4 hours of blood sampling the investigators
will serve volunteers an all-you-can-eat meal of sandwich and measure how must they ate.
- On day two volunteers will drink a sodium chloride solution. Furthermore, the
investigators administrate intravenous D/L sodium lactate in order to reach the same
plasma [lactate] on day 2 as was done on day 1. The rest of day two is identical to day
1.