A 70-year-old man with a history of osteoarthritis has been taking Ibuprofen 600 mg three times daily for chronic knee pain. During a routine check-up, his blood pressure is found to be elevated at 160/95 mmHg, up from his usual 135/85 mmHg. Laboratory tests reveal an elevation in his kidney function tests and serum potassium level. Which of the following adverse effects of NSAIDS best explains these findings?