L cells are a type of enteroendocrine cell primarily found in the ileum and large intestine (colon), with some also present in the duodenum and jejunum. Their primary function is the secretion of several important hormones.
Hormones Secreted by L Cells:
L cells are responsible for secreting the following hormones:
- Glucagon-like peptide-1 (GLP-1): An incretin hormone that stimulates insulin release from the pancreas after eating, thereby helping to lower blood glucose levels.
- Peptide YY3-36 (PYY3-36): A hormone that reduces appetite and slows gastric emptying, contributing to feelings of fullness after a meal.
- Oxyntomodulin: A hormone that inhibits gastric acid secretion and stimulates insulin release. It also has anorexigenic (appetite-reducing) effects.
- Glucagon-like peptide-2 (GLP-2): A hormone that promotes intestinal growth and enhances intestinal function.
Location of L Cells:
| Location | Description |
|---|---|
| Ileum | Primary location; plays a key role in sensing undigested nutrients arriving from the small intestine. |
| Large Intestine (Colon) | Another primary location; contributes significantly to overall hormone secretion. |
| Duodenum | Found in smaller numbers; contributes to early hormonal responses to nutrient intake. |
| Jejunum | Similar to the duodenum, L cells in the jejunum contribute to early hormonal responses, though in relatively smaller amounts. |
In summary, L cells play a crucial role in regulating glucose homeostasis, appetite, and intestinal function through the secretion of various hormones.
