K+ secretion from the loop of Henle is decreased by

Potassium-sparing diuretics act in the collecting tubule to inhibit Na+ reabsorption and K+ excretion. Spironolactone is a synthetic steroid that antagonizes aldosterone at intracellular cytoplasmic receptor sites. The spironolactone-receptor complex is inactive. That is, it prevents translocation of the receptor complex into the nucleus of the target cell and, therefore, it cannot bind to DNA. This results in a failure to produce proteins that are normally synthesized in response to aldosterone. These mediator proteins normally stimulate the Na+/K+-exchange sites of the collecting tubule. Thus, a lack of mediator proteins prevents Na+ reabsorption and, therefore, K+ and H+ secretion.Ref: Lippincott's Illustrated Reviews: Pharmacology, 5th edition, Page No: 286