GO:0097254

Secretion of substances from peritubular capillaries into the renal tubules to be incorporated subsequently into the urine. Substances that are secreted include organic anions, ammonia, potassium and drugs. [GOC:rph, http://en.wikipedia.org/wiki/Renal_secretion#Secretion, http://fau.pearlashes.com/anatomy/Chapter%2041B/Chapter%2041B.htm, PMID:10049739]