A 52-year-old man from rural Maharashtra presents with a 6-month history of progressive weakness, polyuria, and polydipsia. On examination, blood pressure is 168/104 mmHg. Laboratory investigations reveal: serum sodium 148 mEq/L, serum potassium 2.8 mEq/L, serum bicarbonate 32 mEq/L, and plasma renin activity is suppressed (0.3 ng/mL/hr; normal 0.5–1.5). Plasma aldosterone is markedly elevated at 28 ng/dL (normal <15). Abdominal CT shows a 2 cm left adrenal nodule. Which mechanism best explains the suppressed renin activity in this patient?