Portal system in amphibians is
Amphibians possess both hepatic and renal portal systems. Hepatic portal collects deoxygenated nutrient-rich blood from stomach, intestine, spleen via hepatic portal vein into hepatic sinusoids for detoxification, glycogen storage and plasma protein synthesis before returning to sinus venosus via hepatic veins. Renal portal connects veins from hindlimbs and pelvis to kidney peritubular capillaries enabling tubular secretion and reabsorption before caval return, aiding nitrogenous waste handling. Both present well developed not absent, double circulation separate phenomenon, illustrates ectothermic low-pressure pattern with portal routes.
Ref: Romer Vertebrate Body Portal Systems; NCERT Class 11 Chapter 18 Portal Circulation Amphibians