- Vitamin D is a steroid produced in the skin through a reaction between cholesterol and sunlight.
- It is an important part of a healthy body, being a building block for steroids such as the sex hormones, and the hormones of the adrenal cortex.
- Little is known about the steroids associated with these structures in hagfish.
- One of the steroids it produces is cortisol, which increases the supply of glucose in the blood.
- So far, all the sex pheromones found in fish have turned out to be steroids and prostaglandins.