Increased Renin Activity after Cold Storage of Human Plasma

Abstract

The velocity of angiotensin generation during incubation for 3 h at 37 °C increased up to 600% if plasma (EDTA) from normal men was first preincubated for 3 days at 4 °C. Longer preincubation (9–31 days) generally resulted in additional potentiation that continued to be expressed during incubation periods of 3–48 h at 37 °C. The effect is not abolished in the presence of up to 200 μg/ml of neomycin sulfate. Recovery of synthetic angiotensin I added to both cold-stored and control plasma is about 90% after 3 h of contact at 4 °C. The cause of potentiation has not been established, but possibilities under investigation include renin activation and preferential degradation of a renin inhibitor.

Pathophysiological Significance of Plasma Total Renin and Prorenin in Patients with Diabetes Mellitus.

“…HUMAN plasma contains a large amount of inactive renin, which can be activated by enzymatic digestion with trypsin [1], acid treatment [2] and cryoactivation [3,4]. Evidence in the literature has shown that plasma inactive renin is prorenin, a biosynthetic precursor of renin [5][6][7][8].…”

“…Plasma inactive renin, viz. prorenin, has been of interest because of its significant increase in certain pathological states including renin secreting tumors [9,10] and diabetes mellitus [11,12] has been reported to be significantly increased [11,12] and to correlate with diabetic complications [12][13][14][15][16][17] Plasma prorenin has been determined by enzyme kinetic assay after activation by various pretreatments [1][2][3][4] in which the angiotensin I generated by plasma in vitro is measured by radioimmunoassay. The plasma renin activity, however, can be affected by the amount of plasma angiotensinogen.…”

The changes in active and inactive renin induced by various maneuvers in hypertensive patients.

“…Inactive renin can be activatReceived August 24, 1984; accepted for publication April 22, 1986. 169 ed in vitro by acidification (Skinner et al 1975), low temperature (Osmond et al 1973;Sealey and Laragh 1975), or trypsin and other proteolytic enzymes (Day et al 1975;Sealey et al 1979). However, in vivo, the conversion of inactive renin to active renin is not yet proved or disproved.…”

Active, inactive and total renin concentrations in plasma of hypertensive patients.

“…The latter can be converted in vitro to active form by acidification (Skinner et al 1975), low temperature (Osmond et al 1973;Sealey and Laragh 1975), treatments with trypsin and other proteolytic enzymes (Day et al 1975;Sealey et al 1979). Inactive renin has been proposed to be either a proenzyme of normal active renin (Sealey et al 1977 a ;Hsueh et al 1981), or renin bound by its inhibitor protein (Leckie and McGhee 1980).…”