Anyone who has had a couple of drinks may well spend some time traipsing back and forth to the WC. The increased urine output is not caused by alcohol's direct action on the kidneys and is not simply due to the amount of liquid consumed. This phenomenon is related to the effect of alcohol on the posterior portion of the pituitary gland, located at the base of the brain. The pituitary secretes a hormone regulating the amount of urine produced. As the pituitary is affected by alcohol, too little of the hormone is released, and the kidneys form a larger than normal amount of dilute urine. This effect is most pronounced when alcohol is being absorbed and the blood alcohol level is rising.
The liver is very sensitive to the acute effects of alcohol. (See Chapter 5 for more information about the long-term effects of alcohol on the liver.) It has been demonstrated that intake of even relatively small amounts of alcohol (1 to 2 ounces) by nonalcoholics can lead to accumulation of fat in liver cells.
The liver performs an incredible number of different functions—a very important one is its role in maintaining a proper blood sugar level. Sugar (the body's variety, called glucose) is the only source of energy that brain cells can use. Because the brain is the master control center of the body, an inadequate supply of food has far-reaching consequences. When alcohol is present in the system, the liver devotes all of its attention, so to speak, to metabolizing it. There is a stored form of glucose in the liver (glycogen), which is usually readily available. However, if it is not present because of an inadequate diet or fasting for a day or two, the liver will normally go through a more complicated biochemical process to transform other nutrients such as protein into glucose. However, this complicated maneuver is blocked by the presence of alcohol. In these cases hypoglycemia can result. In a hypoglycemic state there is a below-normal concentration of blood sugar. The brain is deprived of its proper nourishment. Symptoms include hunger, weakness, nervousness, sweating, headache, tremor. If the level is sufficiently depressed, coma can occur. Although hypoglycemia may be more likely and more severe in individuals who already have liver damage from chronic alcohol use, it can occur in otherwise normal people with healthy livers who have been drinking heavily and have not been eating properly for as little as 48 to 72 hours.
In individuals with adequate diets, other metabolic effects of alcohol may cause abnormally high levels of blood glucose, called hyperglycemia, a state similar to that which occurs in diabetics. In view of its potentially significant effects on blood sugar levels, the danger posed by alcohol for the diabetic is obvious.
The liver also plays an important role in the metabolism of other drugs. The presence of alcohol can interfere with this and in part be responsible for some alcohol-drug interactions. As mentioned before, the liver enzyme ADH is essential to the metabolism of alcohol. Quantitatively it is the liver's major means of metabolizing alcohol. The liver does have a "backup system," however. This secondary system is called MEOS (short for microsomal ethanol oxidizing system), and it is located in certain intracellular structures called microsomes. Probably only after long-term heavy drinking this secondary system begins to help out significantly in the metabolism of alcohol, yet it is mentioned here because it is a major system in metabolizing other drugs. Acutely the MEOS activity is inhibited dramatically by the presence of alcohol. Therefore, other drugs are not broken down at the usual rate. If other drugs in the system have a depressant effect similar to that of alcohol, this can be serious because the central nervous system will be subjected to both simultaneously. However, other problems can also result with other drugs. Suppose someone is taking a prescription drug, such as Dilantin or Coumadin, at set intervals and also drinks. The presence of alcohol acutely interferes with the metabolism of the medication, thus when the next scheduled dose is taken substantial amounts of the earlier dose remain, and cumulative toxic or side effects may occur.