Lecture Notes: Lipids and Their Functions

Introduction

• Personal Experience: Speaker shares an experience of back and neck pain from long bike rides.
• Medication: Prefers using NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) for pain relief.

NSAIDs

• Examples: Aspirin and Ibuprofen (Motrin).
• Function: Reduce pain caused by muscle inflammation by inhibiting production of prostaglandins.
• Prostaglandins: Lipid molecules signaling inflammation.

Lipids Overview

• Types of Lipids:
  • Hydrolyzable: Can be broken down into smaller units.
  • Non-hydrolyzable: Cannot be broken down, mainly function in signaling.

Prostaglandins

• Category: Part of non-hydrolyzable lipids.
• Class: Belong to a group of compounds called eicosanoids (Greek 'eicosi' = 20, indicating 20 carbons).
• Function:
  • Signal inflammation.
  • Lower blood pressure.
  • Reduce gastric secretions.
  • Inhibit platelet aggregation.

Other Non-Hydrolyzable Lipids

1. Steroids

• Structure: Tetracyclic (four-ring) lipids.
  • Three 6-membered rings and one 5-membered ring.
• Examples:
  • Cholesterol
  • Testosterone (sex hormone)
  • Progesterone (sex hormone)
  • Corticosteroids (cortisone, aldosterone)
• Function: Signaling lipids involved in puberty and other physiological processes.

2. Fat-Soluble Vitamins

• Function: Act as co-factors aiding enzymatic functions.
• Examples:
  • Vitamin A (Retinol): Light sensitivity, healthy mucus membranes.
  • Vitamin D: Regulates phosphorus and calcium metabolism. Deficiency can lead to bone diseases like rickets and osteoporosis.
  • Vitamin E: Antioxidant protecting neurological function.
  • Vitamin K: Regulates synthesis of prothrombin for blood clotting. Deficiency can cause bleeding issues.

Summary

• Non-Hydrolyzable Lipids: Primarily function as signaling molecules or co-factors (vitamins).
• Fat-Soluble Vitamins: A, D, E, and K are crucial for various bodily functions and fit into the broader category of non-hydrolyzable lipids.

This lecture provides an overview of the role of specific lipids in the body, highlighting their structural categories and functions, particularly focusing on NSAIDs like aspirin and ibuprofen, and the broader implications of non-hydrolyzable lipids like prostaglandins, steroids, and fat-soluble vitamins.