A hormone imbalance can cause high blood sugar, known as hyperglycemia. Hormones are the body’s chemical messengers, released by the endocrine system to regulate nearly every bodily process, including metabolism. When these regulatory hormones are too high or too low, the delicate balance of glucose control is disrupted. This often leads to excessive glucose remaining in the bloodstream instead of moving into cells for energy.
The Essential Role of Insulin in Glucose Control
Insulin, a hormone produced by the beta cells of the pancreas, is the primary regulator responsible for lowering blood glucose. After food is consumed, glucose enters the bloodstream, signaling the pancreas to release insulin. Insulin then acts like a key, unlocking cell walls to allow glucose to enter muscle, fat, and liver cells for energy or storage.
An imbalance in insulin function is the most common cause of high blood sugar, manifesting as either insulin deficiency or insulin resistance. Insulin deficiency occurs when the pancreas produces too little or no insulin, meaning the “key” is missing and glucose cannot enter the cells. Insulin resistance develops when the cells stop responding effectively to the insulin signal, essentially ignoring the “key.” The pancreas attempts to compensate by producing more insulin, but if this compensatory mechanism fails, blood glucose levels rise. This resistance prevents glucose uptake and signals the liver to continue producing glucose, worsening the hyperglycemia.
Hormones That Drive Blood Sugar Up
The body maintains glucose balance using “counter-regulatory” hormones that actively raise blood sugar. These hormones ensure the brain and muscles have enough fuel during times of stress or fasting. When these counter-regulatory hormones are overproduced due to an endocrine imbalance, they overwhelm insulin’s action and cause persistent hyperglycemia.
Glucagon
Glucagon, made by the pancreas’s alpha cells, works opposite to insulin. When blood sugar drops, glucagon signals the liver to convert stored glucose (glycogen) back into usable glucose via glycogenolysis. Glucagon also promotes gluconeogenesis, which is the creation of new glucose from non-carbohydrate sources like amino acids, significantly raising blood sugar levels.
Cortisol
Cortisol, the stress hormone, is a glucocorticoid released by the adrenal glands. It promotes new glucose production in the liver while reducing the sensitivity of muscle and fat cells to insulin, inducing insulin resistance. Sustained high levels of cortisol, such as during chronic stress, ensure a constant supply of glucose in the blood, leading to chronic high blood sugar.
Epinephrine
Epinephrine, also known as adrenaline, provides a rapid burst of energy during a “fight-or-flight” response. It acts quickly on the liver to accelerate glycogenolysis, releasing stored glucose into the bloodstream almost instantly. Epinephrine also signals fat cells to break down, supplying additional fuel, which contributes to the temporary spike in blood glucose.
Growth Hormone
Growth hormone, released by the pituitary gland, promotes new glucose creation and directly inhibits insulin action in muscle and fat tissue. An excess of this hormone can cause significant insulin resistance. This requires the pancreas to produce much larger amounts of insulin to maintain blood sugar control.
Endocrine Conditions Linked to Hyperglycemia
Specific endocrine disorders are characterized by the abnormal secretion of counter-regulatory hormones, leading to secondary hyperglycemia, including:
- Cushing’s Syndrome results from prolonged exposure to excess cortisol, causing profound insulin resistance and increased glucose production.
- Acromegaly involves the overproduction of growth hormone, typically from a pituitary tumor, which creates a high degree of insulin resistance.
- Glucagonoma is a rare tumor of the pancreatic alpha cells that secretes excessive amounts of glucagon, leading to uncontrolled glucose release from the liver.
- Polycystic Ovary Syndrome (PCOS), a common disorder in women, is strongly associated with severe insulin resistance.
- Thyroid hormone imbalances, such as in hyperthyroidism, can indirectly affect glucose metabolism by increasing the rate at which glucose is absorbed and produced.
Diagnosing and Addressing Hormonal Causes
When hyperglycemia is suspected to be of hormonal origin, a physician employs specific diagnostic tests to measure the levels of suspected hormones. For conditions like Cushing’s Syndrome, tests may include measuring cortisol in the saliva late at night or in a 24-hour urine collection. Diagnosing Acromegaly often involves measuring insulin-like growth factor 1 (IGF-1) and performing an oral glucose tolerance test (OGTT) to see if the growth hormone level fails to suppress after glucose intake.
The primary approach to addressing hormonally-driven hyperglycemia is to treat the underlying endocrine disorder, rather than simply managing the blood sugar. Normalizing the hormone levels, such as surgically removing a tumor causing excess cortisol or growth hormone, often resolves the hyperglycemia completely. This targeted treatment of the root cause is necessary for achieving long-term and sustainable glucose control.