RENAL CIRCULATORY DYNAMICS AND URINARY PROTEIN EXCRETION DURING INFUSIONS OF l-NOREPINEPHRINE AND l-EPINEPHRINE IN PATIENTS WITH RENAL DISEASE 12

Fixed and Reproducible Orthostatic Proteinuria. Iii. Effect of Induced Renal Hemodynamic Alterations Upon Urinary Protein Excretion*

“…He suggested tentatively that a diminished glomerular blood flow might permit an increased transfer of protein across the capillary wall by lengthening the exposure time of protein molecules to the endothelial surfaces of the glomerular capillaries. As in the present study, he concluded that changes of filtration rate and filtration fraction were not the major hemodynamic determinants of an increased glomerular passage of protein (24).…”

“…King has proposed that the normal filtration fraction elevation of orthostasis is most causally related to the appearance of orthostatic proteinuria (7). Others have suggested that filtration rate and renal blood flow are of equal or greater importance in other forms of proteinuria (24,26). Although only limited conclusions are permitted by the present observations, diminished renal blood flow appears to be of most hemodynamic importance to the occurrence of fixed and reproducible orthostatic proteinuria.…”

“…Regardless of whether vascular adjustments in this condition are normal or abnormal, several observers have emphasized their contribution to urinary protein excretion in both patients with orthostatic proteinuria and with overt forms of renal disease (5,6,24,25). General agreement has not been reached as to which renal hemodynamic parameter is of most importance in this regard.…”

“…Its exact definition must await better knowledge of the fundamental process responsible for the passage of protein molecules across capillary walls, a problem which has been the subject of several recent communications (24,26,28). In studies of patients with obvious renal disease, Lathem demonstrated a correlation between the relative fall of PAH clearance and the rise of protein clearance during the administration of catecholamines (24). He suggested tentatively that a diminished glomerular blood flow might permit an increased transfer of protein across the capillary wall by lengthening the exposure time of protein molecules to the endothelial surfaces of the glomerular capillaries.…”

Effects of endurance exercise on the urinary proteome analyzed by 2‐D PAGE and Orbitrap MS

“…The hypothesis that the negative charge of the glomerular wall is neutralized under increased blood acidity would indicate an increase in acidic proteins [2,13,14]. Another idea of proteinuria connected to changes in hemodynamics would also increase the amount of neutral and acidic proteins and not yield the opposite state [15]. The obviously decreased excretion of acidic proteins cannot be explained now but indicates additional parameters or mechanisms of proteinuria and should be further investigated.…”