renal system process excretion renal tubular secretion https://github.com/geneontology/go-ontology/issues/22368 2012-03-05T02:03:58Z biological_process GO:0097254 The elimination of substances from peritubular capillaries (or surrounding hemolymph in invertebrates) into the renal tubules to be incorporated subsequently into the urine. Substances that are secreted include organic anions, ammonia, potassium and drugs. pr