Spinal cord hemisection between T2 and T3 inhibits compensatory adrenal growth when the contralateral but not the ipsilateral [rat] adrenal is removed (P < 0.01). Pretreatment of left adrenals with 1 or 2% lidocaine, but not with saline, before removal inhibits compensatory right adrenal growth that is normally observed at 12 h (P < 0.01). These results provide further functional evidence that afferent and efferent neural elements mediate adrenal growth after unilateral adrenalectomy.