The hormone ADH (Antidiuretic Hormone), also known as vasopressin, is one of the most important hormones regulating the body’s fluid balance. It is secreted by the posterior pituitary gland in response to changes in salt concentration or a drop in blood pressure, and it works to increase water reabsorption in the kidneys, directly affecting blood volume and pressure. Studying ADH is particularly important for understanding the development of chronic hypertension, as any disruption in its secretion may lead to an imbalance in water and sodium, increasing the risk of cardiovascular and renal complications. Workshop Objectives 1. Explain the mechanism of ADH secretion and regulation. 2. Understand its role in maintaining water and electrolyte balance in the body. 3. Discuss the relationship between ADH excess or deficiency and chronic blood pressure disorders. 4. Review the latest therapeutic approaches related to fluid regulation. Section 1: Physiology of ADH • Secreted by the posterior pituitary gland. • Triggers for secretion: • Increased blood salt concentration (osmolarity). • Low blood pressure or reduced blood volume. • Functions: • Increase the permeability of kidney collecting ducts to water. • Reduce water loss through urine. • Maintain blood volume and pressure. Section 2: ADH and Water Balance • Reduces urine volume and increases its concentration. • Regulates blood volume and electrolyte concentration, maintaining fluid balance. • Any imbalance in ADH leads to: • Excess secretion: Water retention and increased blood volume → high blood pressure. • Deficiency: Excessive water loss → low blood pressure and dehydration. Section 3: Impact of ADH on Chronic Hypertension • Chronic elevation of ADH is associated with increased vascular resistance and high blood pressure. • Contributes to long-term cardiovascular and renal complications. • Proper regulation of ADH secretion and a balanced diet can reduce the risk of complications. Section 4: Clinical Applications • Measuring ADH levels in the blood to assess blood pressure disorders. • Using ADH-regulating drugs in cases of water retention or deficiency. • Monitoring fluid balance as part of comprehensive treatment for patients with chronic hypertension. Conclusion ADH is a key hormone in regulating body water balance and has a direct impact on blood pressure. Understanding its mechanism helps doctors and researchers develop better therapeutic strategies to reduce the complications of chronic hypertension and improve patient quality of life. Presented by: Dr. Hazem Yahya Saeed Al-Mustaqbal University is the first university in Iraq Department of Medical Laboratory Techniques – First in the Iraqi National Ranking.