1) The human body produces endogenous opioids that help alleviate pain.

2) Endogenous melatonin levels increase in the evening to signal to the body that it's time to sleep.

3) Stress can trigger the release of endogenous cortisol in the body.

4) Endogenous growth factors play a key role in tissue repair and regeneration.

5) The endogenous generation of heat helps regulate body temperature.

6) Endogenous stem cells have the potential to differentiate into various cell types.

7) Endogenous depression is characterized by a chemical imbalance in the brain.

8) Endogenous retroviruses are remnants of viral DNA integrated into the human genome.

9) Endogenous enzymes help break down food in the digestive system.

10) Researchers are studying the effects of endogenous cannabinoids on the body's endocannabinoid system.