A patient Information Guide to Insulin, Glucagon, Somatostatin & Gastrin.

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A patient Information Guide to Insulin, Glucagon, Somatostatin & Gastrin.

The human pancreas is an amazing organ with two main functions: [1] to produce

pancreatic endocrine hormones (e.g., insulin & glucagon) which help regulate

many aspects of our metabolism and [2], to produce pancreatic digestive enzymes.

The hormone function of the pancreas is the emphasis of this portion of

Endocrine Web ~ this is referred to as the Endocrine Pancreas. Pancreatic

production of insulin, somatostatin, gastrin, and glucagon plays an important

role in maintaining sugar and salt balance in our bodies and therefore any

problem in the production or regulation of these hormones will manifest itself

with problems with blood sugar and fluid / salt imbalances.

The digestive portion of the pancreas makes up more than 90 percent of its total

cell mass. The digestive (or exocrine) pancreas is responsible for making

digestive enzymes which are secreted into the intestines to help digest (break

down) the food we eat. These enzymes digest proteins, fats, and carbohydrates

into much smaller molecules so our intestines can absorb them. The picture

above is an accurate representation of the pancreas which lies next to the

duodenum (the first part of the small intestine right after the stomach). The

actual size of the pancreas is similar to a banana which has been stepped

on...it has a slight curve to it, and its about the same length, width, and

thickness. The yellow " tube " running through the middle of the pancreas is

called the pancreatic duct. It drains all the digestive enzymes from the

pancreatic cells where they are made into the duodenum where they mix with food

as it comes out of the stomach.

The Endocrine Pancreas

The emphasis of the remainder of these pages within Endocrine Web is on the

Endocrine Pancreas. Approximately 5 percent of the total pancreatic mass is

comprised of endocrine cells. These endocrine cells are clustered in groups

within the pancreas which look like little islands of cells when examined under

a microscope. This appearance led to these groups of pancreatic endocrine cells

being called " Pancreatic Islets " . Within pancreatic islets are cells which make

specific pancreatic endocrine hormones, of which there are only a few (the most

famous of course being insulin). These cells within the islets are called

" Pancreatic Islet Cells " .

Pancreatic islets are scattered throughout the pancreas. Like all endocrine

glands, they secrete their hormones into the bloodstream and not into tubes or

ducts like the digestive pancreas. Because of this need to secrete their

hormones into the blood stream, pancreatic islets are surrounded by small blood

vessels. This relationship is shown in the picture of a pancreatic islet where

islet cells are secreting their hormones into nearby blood vessels. Remember,

the purpose of endocrine cells is to make hormones which are secreted into the

blood stream where they gain access to other cells very far away with the goal

of making those cells respond in a specific fashion.

Pancreatic Endocrine Hormones and Their Purpose

Insulin

Purpose: Regulate blood glucose (sugar) in the normal range (lots more

about this)

Action: Forces many cells of the body to absorb and use glucose thereby

decreasing blood sugar levels

Secreted in response to: High blood glucose

Secretion inhibited by: Low blood glucose

Disease due to deficient action: Diabetes (large section of Endocrine

Web is devoted to Diabetes).

Disease due to excess action: Hypoglycemia

Tumor called: Insulinoma. Please see this link for more information

" Insulinoma.Net " .

Glucagon

Purpose: Assist insulin in regulating blood glucose (sugar) in the normal

range (actions are opposite of insulin)

Action: Forces many cells of the body to release (or produce) glucose

(increasing blood sugar)

Secreted in response to: Low blood glucose

Secretion inhibited by: High blood glucose

Disease due to deficient action: Some times nothing, sometimes

hypoglycemia

Disease due to excess action: Hyperglycemia

Tumor called: Glucagonoma (new page about this soon)

Somatostatin

Purpose: Regulate the production and excretion of other endocrine tumors

Action: Slows down production of insulin, glucagon, gastrin, and other

endocrine tumors

Secreted in response to: High levels of other endocrine hormones

Secretion inhibited by: Low levels of other endocrine hormones

Disease due to deficient action: Poorly defined

Disease due to excess action: Diabetes (inhibits insulin production),

gallstones, and dietary fat intolerance.

Tumor called: Somatostatinoma (new page about this soon)

Gastrin

Purpose: Assist in digestion within the stomach

Action: Induce acid producing cells of the stomach to produce acid

Secreted in response to: Food in the stomach and intestines

Secretion inhibited by: Absence of food in stomach and intestines

Disease due to deficient action: Poorly defined, some times no symptoms at

all

Disease due to excess action: Stomach ulcers due to excess stomach acid

Tumor called: Gastrinoma (also called Zollinger Ellison Syndrome) (new page

about this soon)

Vasoactive Intestinal Peptide (VIP)

Purpose: Help control water secretion and absorption from the intestines

Action: Causes intestinal sells to secrete water and salts into the

intestines (inhibit absorption)

Secreted in response to: Unclear

Secretion inhibited by: Unclear

Disease due to deficient action: No symptoms at all

Disease due to excess action: Severe watery diarrhea and salt (potassium)

imbalances

Tumor called: VIPoma (new page about this soon)

I hope this finds you and yours well

Mark E. Armstrong

casca@...

www.top5plus5.com

PAI NW Rep

ICQ #59196115