title: Plasma 18-hydroxycorticosterone during continuous ambulatory peritoneal dialysis.
abstract: Continuous ambulatory peritoneal dialysis (CAPD) entails the continuous presence of hypertonic dialysate in the peritoneal cavity. We postulated that the continuous, gradual ultrafiltration produces chronic activation of the renin-angiotensin system and the adrenal zona glomerulosa. To explore this hypothesis, we measured plasma levels of PRA, active renin (AR), total renin (TR), inactive renin (IR), 18-hydroxycorticosterone (18-OH-B), and aldosterone (PAC) under basal and stimulated conditions. At 0800 and 1200 hr after overnight recumbency, plasma levels of PRA, AR, TR, IR, and 18-OH-B were elevated above the range for sodium-replete recumbent normal subjects. PAC, however, was normal. The increase in TR was due predominantly to an increase in AR. After the combined stimulus of 4 hr ambulation and the ultrafiltration induced by a 2 L exchange, plasma levels of PRA, AR, TR, IR, and PAC were within the range for sodium-replete upright normal subjects. Plasma 18-OH-B levels, however, remained markedly elevated. Graded intravenous infusion of ACTH at rates of 0.03 to 10 ng/min demonstrated that the threshold for an ACTH-stimulated rise in plasma 18-OH-B and PAC is at least as low as that for cortisol and corticosterone. We conclude that CAPD produces activation of the renin-angiotensin system. The high circulating levels of PRA, AR, and, presumably, angiotensin II result in increased secretion of 18-OH-B by the adrenal zona glomerulosa.
mesh_terms: D015069:18-Hydroxycorticosterone / Q000096:biosynthesis / Q000097:blood*; D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage; D000450:Aldosterone / Q000097:blood; D003345:Corticosterone / Q000031:analogs & derivatives*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis; D010531:Peritoneal Dialysis, Continuous Ambulatory; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood; D012964:Sodium / Q000097:blood
chemical_list: D000450:Aldosterone; D015069:18-Hydroxycorticosterone; D000324:Adrenocorticotropic Hormone; D012964:Sodium; D012083:Renin; D011188:Potassium; D003345:Corticosterone; D006854:Hydrocortisone