The pancreas is an endocrine gland, but that’s only part of the story. It actually serves double duty as both an endocrine and an exocrine gland, making it one of the few organs in the body with this dual role. About 95% of the pancreas is dedicated to its exocrine function (producing digestive enzymes), while only 1 to 3% of its total weight consists of endocrine tissue. So while calling it an endocrine gland is technically correct, calling it a “mixed gland” is more accurate.
What Makes It an Endocrine Gland
Endocrine glands release hormones directly into the bloodstream, and the pancreas does exactly that. Scattered throughout the organ are 1 to 2 million tiny clusters of hormone-producing cells called islets of Langerhans. Despite making up such a small fraction of the pancreas by weight, these clusters play an outsized role in keeping your metabolism stable.
The islets contain several specialized cell types, each responsible for a different hormone. The two most important are alpha cells, which produce glucagon, and beta cells, which produce insulin. Together, these two hormones form the primary system your body uses to control blood sugar. A third type, delta cells, produces a hormone called somatostatin that acts as a brake on the whole system, preventing insulin and glucagon from overshooting when they’re no longer needed.
How Insulin and Glucagon Work Together
After you eat a meal, glucose from your food floods into the bloodstream. Beta cells detect this rise and release insulin, which drives glucose into your muscles, fat tissue, and liver, where it gets stored for later use. At the same time, glucagon levels drop because the liver doesn’t need to produce extra glucose when plenty is already available.
Between meals and overnight, the opposite happens. Insulin levels fall to a low, steady baseline, and glucagon rises. Glucagon signals the liver to break down its stored glycogen (a starch-like reserve) back into glucose and release it into the blood. It also triggers the liver to create new glucose from other raw materials and promotes the breakdown of fat for energy. This back-and-forth cycle keeps your blood sugar within a narrow, healthy range around the clock.
Somatostatin fine-tunes this process. When blood sugar drops low, it inhibits further insulin release so levels don’t crash. When blood sugar is high, it can suppress glucagon to prevent unnecessary glucose production. It essentially prevents either hormone from overcorrecting.
The Exocrine Side: Digestion
The vast majority of the pancreas, roughly 95%, is exocrine tissue. Instead of releasing hormones into the blood, these cells produce digestive enzymes and channel them through a duct into the duodenum, the first section of the small intestine. This is the key distinction between endocrine and exocrine: endocrine glands secrete into the bloodstream, while exocrine glands secrete through ducts to a specific destination.
The pancreas produces three major categories of digestive enzymes. Proteases like trypsin and chymotrypsin break proteins down into smaller and smaller fragments. Pancreatic lipase splits dietary fat into components small enough to absorb through the intestinal wall. Amylase breaks starches down into simple sugars. Without these enzymes, your body couldn’t extract most of the nutrients from the food you eat. The pancreas also produces several other enzymes, including elastase and gelatinase, that handle more specialized digestive tasks.
Where the Pancreas Sits in Your Body
The pancreas is a long, flat organ tucked behind the stomach and in front of the spine. Its wider end, called the head, nestles into the curve of the duodenum on the right side of your abdomen. This positioning allows the pancreatic duct to deliver digestive enzymes directly where food arrives from the stomach. The organ tapers to a thinner tail that extends to the left, ending near the spleen. The liver and gallbladder sit nearby as well, forming a tightly packed cluster of digestive organs.
What Happens When the Endocrine Pancreas Fails
Because the endocrine portion of the pancreas is so small, even modest damage can have serious consequences. The most well-known result of endocrine pancreatic failure is diabetes. In Type 1 diabetes, the immune system destroys the beta cells, eliminating insulin production almost entirely. In Type 2 diabetes, beta cells still produce insulin, but the body’s response to it becomes impaired over time.
There’s also a less commonly discussed form called pancreatogenic diabetes (sometimes classified as Type 3c), which develops when chronic pancreatitis or repeated bouts of severe acute pancreatitis physically damage the islets. This form is particularly difficult to manage because the destruction affects multiple hormone-producing cell types, not just beta cells. Losing glucagon production alongside insulin production creates unpredictable swings between high and low blood sugar. Endocrine insufficiency develops in roughly 56% of severe acute pancreatitis cases and 23% of mild cases.
Exocrine failure, by contrast, looks very different. When the enzyme-producing tissue is damaged, the result is poor digestion rather than blood sugar problems: fatty stools, weight loss, and nutrient deficiencies. In chronic pancreatitis, both sides often deteriorate together over time, but the endocrine and exocrine consequences require entirely separate management.