An elevated blood sugar level, known as hyperglycemia, is most often associated with diabetes, but it can also result from an imbalance in other regulating hormones. Hormones are powerful chemical messengers that coordinate almost every function, including the precise control of glucose in the bloodstream. When the endocrine system malfunctions, the resulting excess or deficiency of non-insulin hormones can disrupt glucose homeostasis, leading to sustained high blood sugar. This occurs because many hormones naturally counteract the effects of insulin, the body’s primary glucose-lowering agent.
How the Body Normally Manages Blood Sugar
The body maintains stable blood glucose through a continuous feedback loop involving two hormones produced in the pancreas: insulin and glucagon. After a meal, carbohydrates are broken down into glucose, causing blood sugar levels to rise. This signals the pancreas to release insulin, which allows glucose to enter cells for immediate energy or storage.
Insulin promotes the storage of excess glucose in the liver and muscles as glycogen and in fat cells as triglycerides. Conversely, when blood sugar begins to drop, such as during fasting or intense exercise, the pancreas releases glucagon.
Glucagon signals the liver to break down stored glycogen into glucose (glycogenolysis) and to create new glucose from non-carbohydrate sources like amino acids (gluconeogenesis). This dual-hormone system ensures that the brain and other organs receive a constant supply of fuel, keeping blood glucose within a healthy range.
The Impact of Stress Hormones (Cortisol and Adrenaline)
Hormones released during the stress response are powerful counter-regulatory agents designed to temporarily override insulin’s glucose-lowering action. Cortisol (chronic stress) and adrenaline (epinephrine, acute stress) are the main hormones involved.
Adrenaline triggers the immediate “fight-or-flight” response, signaling the liver to quickly release stored glucose via glycogenolysis. This rapid surge of available energy causes an acute, short-lived spike in blood sugar. Adrenaline also inhibits insulin action, making it harder for cells to absorb the newly released glucose.
Cortisol is a longer-term hormone that helps the body cope with sustained stress. It stimulates gluconeogenesis, signaling the liver to manufacture new glucose from proteins and fats. Chronically elevated cortisol, as seen in conditions like Cushing’s syndrome, promotes widespread insulin resistance in muscle and fat tissue. This forces the pancreas to produce excessive insulin to compensate, which can lead to sustained hyperglycemia.
Systemic Regulators: Thyroid and Growth Hormone
Other hormones governing general body processes, like metabolism and growth, can severely disrupt glucose balance when imbalanced. Thyroid hormones regulate the body’s overall metabolic rate and affect how quickly glucose is absorbed and utilized.
When the thyroid gland is overactive (hyperthyroidism), the accelerated metabolism leads to faster glucose absorption in the gut. Excess thyroid hormone also increases the liver’s glucose production through glycogenolysis and gluconeogenesis, resulting in impaired glucose tolerance. This metabolic overdrive increases insulin resistance in peripheral tissues, further contributing to elevated blood sugar.
Growth Hormone (GH) is another powerful counter-regulatory hormone that opposes insulin’s effects, especially when in excess. GH is naturally released in pulses to repair tissues and signal the liver to produce glucose. However, excessive GH, such as in acromegaly, causes chronic and severe insulin resistance by blocking glucose uptake in muscle and fat cells. The body attempts to overcome this by producing more insulin, but the persistent opposition from surplus GH keeps blood sugar levels high.
Recognizing and Testing for Hormonal Imbalance
Recognizing that high blood sugar may be due to a hormonal imbalance requires looking beyond typical diabetes symptoms. Subtle signs like unexplained weight gain (especially in the midsection) or fatigue that does not improve with rest may suggest a cortisol issue. Unexplained heat intolerance, an elevated heart rate, or unintentional weight loss might point toward an overactive thyroid.
If a healthcare provider suspects a hormonal cause for hyperglycemia, they will order specific diagnostic tests. To check for cortisol issues, a doctor might request a 24-hour urine collection or a late-night salivary test. Thyroid function is assessed using a blood panel that measures thyroid-stimulating hormone (TSH) and active thyroid hormones. Growth Hormone excess is often screened using a blood test for Insulin-like Growth Factor 1 (IGF-1), which reflects average GH levels.