A hormone imbalance can significantly cause high blood sugar, known as hyperglycemia. The endocrine system regulates metabolism and glucose control using chemical messengers. When the levels of these hormones are disrupted—through overproduction or underproduction—the delicate balance of blood sugar is thrown off. This leads to persistently elevated glucose levels, providing a non-dietary explanation for chronic high blood sugar.
How the Body Manages Blood Sugar
The body maintains glucose homeostasis through the coordinated action of two hormones secreted by the pancreas: insulin and glucagon. Insulin instructs cells in muscle, fat, and the liver to absorb glucose from the bloodstream for energy or storage. This action effectively lowers blood sugar after a meal.
Glucagon performs the opposite function, acting to raise blood sugar when levels fall too low, such as during fasting or intense exercise. It signals the liver to convert stored glucose (glycogen) back into glucose and release it into the circulation. Glucagon also promotes gluconeogenesis, the creation of new glucose from non-carbohydrate sources. This push-and-pull mechanism ensures the central nervous system receives a constant energy supply, keeping blood sugar levels within a narrow, healthy range.
The Counter-Regulatory Hormones
Several other hormones naturally oppose insulin’s blood-sugar-lowering action, earning them the name counter-regulatory hormones. These messengers are typically released as part of a stress or survival response to ensure the body has sufficient glucose available for immediate use. The long-term overproduction of these hormones can directly lead to sustained high blood sugar.
Cortisol, a glucocorticoid produced by the adrenal glands, promotes the liver’s production of new glucose and reduces the sensitivity of muscle and fat cells to insulin. Chronic, excessive cortisol levels induce insulin resistance, meaning the body’s cells ignore insulin’s signal, leaving glucose trapped in the bloodstream. Epinephrine, also known as adrenaline, is released during acute stress, rapidly signaling the liver to dump its stored glucose into the blood.
Growth hormone, secreted by the pituitary gland, also raises blood glucose by increasing the liver’s glucose output and reducing the effectiveness of insulin. High levels of growth hormone can cause insulin resistance, leading to elevated blood glucose. When these counter-regulatory hormones are chronically elevated, they overpower insulin’s regulatory effects, resulting in sustained hyperglycemia.
Endocrine Disorders That Cause Hyperglycemia
Chronic hormone excess translates into specific, diagnosable endocrine disorders that cause high blood sugar. These conditions represent a distinct category of diabetes, sometimes referred to as secondary diabetes, where treating the underlying hormonal issue often resolves the glucose imbalance.
Cushing’s Syndrome
Cushing’s Syndrome results from prolonged exposure to high levels of cortisol, often due to a tumor on the pituitary or adrenal gland. The continuous stream of excess cortisol promotes the liver’s glucose production and fosters widespread insulin resistance, disturbing glucose homeostasis.
Acromegaly
Acromegaly is caused by the overproduction of growth hormone, typically from a pituitary tumor. The excess growth hormone directly interferes with insulin’s ability to clear glucose from the blood, leading to glucose intolerance or overt diabetes.
Other Hormonal Causes
Hyperthyroidism, where the thyroid gland produces too much thyroid hormone, accelerates overall metabolism. This includes the rate at which the liver produces and releases glucose, potentially causing mild to moderate hyperglycemia. A rare tumor called a Pheochromocytoma secretes excessive epinephrine and norepinephrine, dramatically increasing liver glucose output and inducing severe insulin resistance.
Diagnosing and Addressing the Imbalance
For individuals experiencing unexplained or persistent hyperglycemia, a healthcare provider investigates a hormonal cause using specialized blood tests. These tests measure circulating levels of hormones like cortisol, growth hormone, or thyroid hormones. Diagnosing conditions like Cushing’s Syndrome or Acromegaly requires dynamic testing, such as hormone suppression or stimulation tests, and specialized imaging like CT scans or MRIs to locate a potential tumor.
Managing this type of high blood sugar differs from standard diabetes care because the focus is on the root cause, not just the resulting high glucose. Treatment aims to restore hormonal balance, which may involve medication to block the effects of the excess hormone or surgery to remove a hormone-secreting tumor. Removing the tumor that causes Acromegaly or Cushing’s Syndrome often leads to significant improvement or complete resolution of the hyperglycemia.