Parkinson’s disease is a progressive neurodegenerative disorder that affects movement control.

While the exact cause of the disease is still unknown, researchers have been studying various factors that may contribute to its development, including hormones. Hormones are chemical messengers that regulate various bodily functions, and imbalances in these hormones can potentially impact the pathogenesis of Parkinson’s disease.

1. Dopamine

Dopamine is a neurotransmitter that plays a critical role in motor control and various other brain functions. In Parkinson’s disease, there is a significant loss of dopamine-producing neurons in a brain region called the substantia nigra.

This loss of dopamine leads to motor symptoms such as tremors, rigidity, and slowed movement. While dopamine is not a hormone, it is closely related to the hormone norepinephrine.

2. Norepinephrine

Norepinephrine, also known as noradrenaline, is a hormone and neurotransmitter that is involved in regulating arousal, attention, and stress responses.

Research suggests that norepinephrine levels are dysregulated in Parkinson’s disease, which could contribute to non-motor symptoms such as sleep disturbances, cognitive impairment, and depression.

3. Estrogen

Estrogen is a predominantly female hormone that regulates reproductive functions and has neuroprotective effects on the brain.

Studies have shown that estrogen levels decline during menopause, and this decline may increase the risk of developing Parkinson’s disease in women. Estrogen replacement therapy has been investigated as a potential protective measure against Parkinson’s disease, although the results have been inconclusive.

4. Testosterone

Testosterone is a male hormone that plays a role in maintaining muscle mass, bone density, and cognitive function. Low testosterone levels have been associated with an increased risk of Parkinson’s disease in men.

However, the exact relationship between testosterone and Parkinson’s disease is still not well understood, and further research is needed to determine the underlying mechanisms.

5. Insulin

Insulin is a hormone that regulates blood sugar levels and metabolism. It is primarily associated with diabetes, but studies have also suggested a potential link between insulin dysregulation and Parkinson’s disease.

Insulin resistance, a condition in which the body’s cells become less responsive to insulin, has been observed in both Parkinson’s disease patients and animal models. This insulin dysregulation may contribute to neuroinflammation and neuronal dysfunction.

6. Melatonin

Melatonin is a hormone that regulates sleep-wake cycles and is primarily produced in the pineal gland.

Disruptions in sleep patterns are common in Parkinson’s disease patients, and studies have shown that melatonin levels are altered in these individuals. It is believed that melatonin dysfunction may contribute to the sleep disturbances experienced by Parkinson’s disease patients.

7. Cortisol

Cortisol is a stress hormone that is released in response to various stressors. Chronic stress has been shown to affect the progression of Parkinson’s disease, and cortisol dysregulation may play a role in this process.

Elevated cortisol levels and abnormal cortisol rhythms have been observed in Parkinson’s disease patients, and these abnormalities may contribute to neurodegeneration.

8. Thyroid Hormones

Thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), play a crucial role in regulating metabolism and brain function.

Studies have indicated that altered thyroid hormone levels may be associated with an increased risk of Parkinson’s disease. Hypothyroidism (low thyroid hormone levels) and hyperthyroidism (excess thyroid hormone levels) have both been linked to an elevated risk of developing Parkinson’s disease.

9. Growth Hormone

Growth hormone is essential for cellular growth, metabolism, and overall body development. Studies have suggested that growth hormone deficiency may be associated with an increased risk of Parkinson’s disease.

Furthermore, growth hormone replacement therapy has shown some beneficial effects in improving motor function and quality of life in Parkinson’s disease patients.

10. Prolactin

Prolactin is a hormone primarily involved in lactation and reproductive functions. It also has immunoregulatory and anti-inflammatory properties.

Some studies have suggested that prolactin levels may be altered in Parkinson’s disease, but the exact role of prolactin in the disease process is still unclear.