Transitory increment in urinary free 19-nor-deoxycorticosterone after diuretic-induced renin stimulation.

19-Nor-deoxycorticosterone (19-nor-DOC) is a potent mineralocorticoid recently identified in human urine. The factors regulating 19-nor-DOC production are unknown; short term dietary sodium depletion or excess has little effect on 19-nor-DOC excretion in human subjects. This study sought to determine if more prolonged renin stimulation could increase 19-nor-DOC production. Six normal subjects were admitted to a metabolic unit. After a 5-day electrolyte balance period, hydrochlorothiazide (50 mg/day) was administered for 28 days. This treatment resulted in acute natriuresis, a more sustained hypokalemia, and secondary hyperaldosteronism lasting throughout the remainder of the study. Despite the sustained secondary hyperaldosteronism, however, urinary 19-nor-DOC extraction, measured by RIA, increased only slightly on day 3 and subsequently decreased to normal values throughout the remainder of the study (19-nor-DOC, 103 +/- 27 ng/day 0, 175 +/- 26 on day 3, 127 +/- 27 on day 28). The results of this study demonstrate only a minor and transient effect on diuretic-induced renin stimulation on 19-nor-DOC production. Therefore, the physiological regulation of 19-nor-DOC is largely independent of the renin-angiotensin system.