Effects of renal denervation on renin release in response to tilting and furosemide

In anesthetized cats head-up tilting for 30 min and infusion of furosemide at 0.75 mg/kg in 30 min significantly raised renin release from the innervated kidney (increments of 90.7±21.4 ng/min on tilting and 105.4±26.4 ng/min after furosemide); a small and inconstant increase from the contralateral denervated kidney (increments of 16.8±16.0 and 16.3±17.7 ng/min, resp.) was abolished by acute bilateral adrenalectomy. Larger doses of furosemide (6.0 mg/kg) could release renin from the denervated kidney also, but the response was still more marked on the innervated side especially in the early period of infusion (increments of 132.7±23.8 and 33.7±23.8 ng/min on innervated and denervated sides at 10 min). The response of the denervated kidney to 6.0 mg furosemide/kg was not affected by adrenalectomy. Stimulation of juxtaglomerular cells by tilting is entirely due to sympathoadrenergic activation; stimulation by furosemide is also entirely neural when the diuretic drug is given in moderate doses, but is partly independent of innervation when larger doses are administered.