Hormonal Feedback Mechanisms – Regulation of Endocrine Function

Introduction

The endocrine system maintains hormonal balance through feedback mechanisms that regulate secretion based on physiological needs. Understanding these mechanisms is crucial for diagnosing endocrine disorders.

Types of Hormonal Feedback

1. Negative Feedback (Most Common)

   • Hormone secretion is inhibited when levels reach an optimal range.
   • Example:
     • Thyroid Hormone Regulation:
       • High T3/T4 → Inhibits TRH (hypothalamus) & TSH (pituitary) → Decreases T3/T4 production.

2. Positive Feedback (Rare, Amplifies Response)

   • Hormone secretion is enhanced to intensify physiological effects.
   • Example:
     • Oxytocin in Labor: Uterine contractions → More oxytocin → Stronger contractions → Birth.

Clinical Relevance

• Defective feedback leads to hormone imbalances (e.g., Cushing’s syndrome, Thyroid disorders).
• Dexamethasone suppression test helps diagnose Cushing’s syndrome.

Conclusion

Hormonal feedback mechanisms maintain homeostasis and prevent endocrine dysfunction. These MBBS notes provide a structured understanding of regulatory pathways.