Dog Adrenal Gland Guide: What is the Adrenal Gland? What are its main functions?

The adrenal gland is one of the most common endocrine organs in dogs. However, due to its relatively unknown nature, many people may not know much about its functions and potential problems. It often takes a considerable amount of time to explain, but pet owners and other family members often say, “The doctor said my dog has kidney problems,” which makes me very nervous. Therefore, let’s discuss in detail what the adrenal gland is.

Functions of the Adrenal Gland

The adrenal gland is located above the kidneys. For cats and dogs, it is situated in front of the kidneys. The size of the adrenal gland is slightly larger than a soybean. Although it appears small, it plays a very important role in the body’s metabolism.

Layered Structure of the Adrenal Gland

The adrenal gland is roughly divided into an inner layer and an outer layer. Each layer is composed of different types of cells, aimed at helping the body cope with various difficult situations, like a small medicine bag filled with tonics.

Outer Layer (Cortex)

The outer layer mainly secretes two hormones, which have complex names. Below is a more straightforward introduction:

1. Anti-stress Hormone: Also known as glucocorticoids, this hormone is secreted when a dog encounters psychological or physiological stress (such as fear, illness, or surgery). Its purpose is to quickly increase the availability of various nutrients when the body faces unpredictable stress, allowing cells to rapidly obtain the necessary nutrients and repair materials to help the dog get through tough times.
2. Blood Pressure Regulation Hormone: Also known as mineralocorticoids, it remotely regulates the kidneys’ reabsorption of water. When a dog is dehydrated or has blood loss, mineralocorticoids will try to retain water in the body to prevent a drop in blood pressure.

Inner Layer (Medulla)

The inner layer mainly secretes life-saving hormones, namely adrenaline and norepinephrine. When the body faces extremely urgent situations (such as a fire or being chased by a dog), these hormones can accelerate the heartbeat and increase blood flow to the muscles, allowing us to run faster and jump higher than others, enhancing reaction speed and increasing the chances of survival.

Potential Problems with the Adrenal Gland

The main problems with all endocrine organs are over-secretion or under-secretion. Each of the above hormones can have issues with over-secretion or deficiency, and the first doctor to discover these problems has the opportunity to name the related diseases. This is why the names of these diseases are often not intuitive.

Over-secretion of Corticosteroids

Hyperadrenocorticism (Cushing’s Disease): This disease was first discovered by Dr. Harvey Cushing in 1932 and is therefore called Cushing’s Disease. It is usually caused by the over-secretion of anti-stress hormones, mainly due to chronic metabolic disorders.

Under-secretion of Corticosteroids

Hypoadrenocorticism (Addison’s Disease): This disease was first discovered by Dr. Thomas Addison in 1855 and is therefore called Addison’s Disease. In this case, both anti-stress and blood pressure regulation hormones are usually deficient. When the body severely lacks blood pressure regulation hormones, it may lead to severe dehydration, low blood pressure, and electrolyte imbalances, which can be life-threatening.

Over-secretion of Blood Pressure Regulation Hormones

Hyperaldosteronism (Conn’s Syndrome): This disease was first discovered by Jerome W. Conn in 1955 and is therefore called Conn’s Syndrome. It causes the body to retain water ineffectively, leading to electrolyte imbalances and ultimately resulting in high blood pressure, high blood sodium, and low blood potassium.

Over-secretion of Life-saving Hormones

Pheochromocytoma: This disease is not named after its discoverer but after the cells involved, called pheochromocytoma. It causes continuous secretion of life-saving hormones, leading to soaring blood pressure and subsequent damage to the cardiovascular system, kidneys, brain, and eyes.

Summary

The adrenal gland secretes a variety of hormones, and when the secretion of these hormones is excessive or insufficient, it can lead to corresponding diseases. Over-secretion is usually caused by tumors and can be treated by surgical removal or drug control; under-secretion is due to the destruction of secretory cells. Fortunately, there are still drugs available for supplementary treatment.

Whether it is over-secretion or under-secretion, these diseases are chronic and require long-term treatment and regular follow-ups.