NCSF Sport Nutrition Specialist Certification (SNS) Practice Test

The liver can produce glucose from which of the following substances?

1. Proteins

2. Lactate

3. Fatty acids

4. Sugars

The correct answer is: Lactate

The liver has the capability to produce glucose through a process known as gluconeogenesis, which primarily involves certain non-carbohydrate sources. Lactate is one of these key substrates. During intense exercise or anaerobic conditions, muscles convert excess pyruvate to lactate. When this lactate is transported to the liver, it can be converted back into glucose through the Cori cycle. This process is essential for maintaining blood glucose levels during periods of fasting or intense physical activity. While proteins can also contribute to gluconeogenesis, this process involves the breakdown of amino acids into intermediates that can enter the gluconeogenic pathway, making lactate a more direct and readily converted substrate. Fatty acids, on the other hand, do not directly contribute to gluconeogenesis because they are converted into Acetyl-CoA, which cannot be converted back into glucose. Sugars, in contrast, are typically utilized for immediate energy rather than being converted into glucose by the liver. Therefore, among the options provided, lactate is the most significant precursor for gluconeogenesis in the liver.