What is the role of the kidneys when the liver cannot detoxify ammonia?

The kidneys play a crucial role in excreting waste products and maintaining homeostasis within the body, including the management of ammonia when the liver's ability to detoxify it is compromised. Under normal circumstances, ammonia, a toxic byproduct of protein metabolism, is converted into urea by the liver, which is then excreted by the kidneys. If the liver is unable to perform this function effectively, the kidneys take on the responsibility of eliminating excess ammonia from the bloodstream.

In this context, the kidneys filter ammonia and convert it into urea, thereby enabling the body to safely eliminate this toxin through urine. This shift reflects the kidneys' ability to adapt to metabolic disturbances and highlights their essential function in detoxifying the body, particularly when the liver's detoxification pathway is impaired.

The other options refer to functions that are unrelated to the kidneys' management of ammonia under these circumstances. Enhancing nutrient absorption primarily involves the intestines, balancing hormone levels is mainly the role of endocrine organs, and aiding in energy metabolism is a function centered in the liver and muscle tissues, rather than the kidneys. Thus, the elimination of toxins, particularly ammonia, accurately captures the kidneys' vital role when liver detoxification is compromised.