1. Drugs known as potasssium -sparing diuretics work by blocking the effects of

Question

1. Drugs known as potasssium -sparing diuretics work by blocking the effects of aldosterone on the kdney. What effect would these drugs have on the amount of urine produced, on the blood pressure, and on potassium ion concentration in the blood? Could these drugs have a negative on the acid-base balance of the body? Explain.

2. The disease diabetes mellitus, type I, is characterized by destruction of the cells that produce insulin in the pancreatic islets. Predict the symptoms and effects of this disease.

3.Explain why an increase in thyroid hormone generally leads to a decrease in thyroid-stimulating hormone (TSH).

Explanation / Answer

1) Potassium sparing diuretics cause diuresis by acting as antagonist to aldosterone competing for its receptor sites or by blocking the epithelial sodium channels. As the name suggets, they decrease potassium excretion by kidneys and increase excretion of sodium. Potassium sparing diuretics can be classified into two types: aldosterone antagonists (spiranolactone and eplerenone) and epithelial sodium channel blockers (amiloride and triamterene).

Potassium sparing diuretics acts by blocking Na-K-ATPase pump present in the distal parts of the nephron, from the late distal tubule to the collecting duct. Active sodium reabsorption takes place in these segments. Sodium ions enter the cell through specific channels present in the luminal membrane and are extruded out of the cell into the peritubular medium by a sodium-potassium exchange pump, the Na-K-ATPase. As a result of blocking this pump, sodium excretion is increased and potassium is spared.

Potassium sparing diuretics causes increased urine output by virtue of its diuretic properties. Blood pressure is decreased. Potassium concentration in blood increases and it causes hyperkalemic metabolic acidosis.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.