Humoral factors in regulation of compensatory renal hypertrophy

Compensatory renal hypertrophy in transplanted kidneys shows that the major regulators are humoral. Crosscirculation experiments are confirmatory indicating further that the regulators are short-lived and must be consistently present during the early phases of hypertrophy. Controls are difficult to achieve in other systems; variables relate to nutrition, means of assay, pharmacokinetics, and abnormalities produced by the experimental model itself. A simple hypothesis to account for the events precipitating renal hypertrophy might integrate the onsets of renal hyperemia soon after contralateral nephrectomy with the activation of pre-existing stimulators specific for the kidney.