Afferent-efferent vessel dysfunction appears to be a specific characteristic of a large subset of patients with essential hypertension.
Exercise renography makes it possible to subdivide essential hypertensives (EHs) into two distinct populations. Fifty to 60% develop exercise-mediated renal dysfunction and a transitory, severe reduction of glomerular filtration. The other subset of EHs does not have exercise-mediated renal dysfunction. We hoped to learn whether the disturbance is also present while EHs rest. Twenty-six EHs and 21 normotensive controls were studied with a resting sequential renogram using Tc-99m-mercaptoacetyl-triglycine (MAG3), a tracer excreted primarily by proximal tubular cells. EHs also had an exercise renogram. All persons had three consecutive 10-min dual-tracer infusion clearance determinations with 111In-DTPA and 131I-hippurate, for the simultaneous determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). To demonstrate the accuracy of the clearance procedure we sought to reproduce Hollenberg's results which show greater flow variability in EH than in normotension. Following this, the variability (VAR) of the GFR and ERPF as well as the variability fraction (VF), the ratio of GFR variability divided into the ERPF variability, were calculated. Hollenberg's results were reproduced. Sixteen of 26 essential hypertensives developed exercise-mediated renal dysfunction. GFR-VAR in EH differed from controls. The VF suggests that EHs with a bilateral abnormal exercise renogram have a more pronounced GFR variability than those EH with a normal exercise renogram. The results point to intraglomerular pressure fluctuations in patients with EH, and the VF suggests that this may be more pronounced in EHs with a bilateral abnormal exercise renogram than in those with a normal exercise renogram. It is hypothesized that the variable GFR provokes renin secretion in EH.
Clorius
J H
JH
German Cancer Research Center, Department of Oncologic Diagnosis and Therapy, Heidelberg. j.clorius@dkfz-heidelberg.de
Schottler
T
T
Haufe
S
S
Zuna
I
I
Reinbold
F
F
van Kaick
G
G
D000328:Adult; D005260:Female; D005919:Glomerular Filtration Rate; D006626:Hippurates; D006801:Humans; D006977:Hypertension, Renal / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D007668:Kidney / Q000098:blood supply / Q000378:metabolism / Q000502:physiology; D008297:Male; D008875:Middle Aged; D004369:Pentetic Acid; D005082:Physical Exertion / Q000502:physiology; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals; D012077:Renal Artery / Q000502:physiology; D012079:Renal Circulation / Q000502:physiology*; D012082:Renal Veins / Q000502:physiology; D012083:Renin / Q000378:metabolism; D012146:Rest / Q000502:physiology; D017263:Technetium Tc 99m Mertiatide; D014655:Vascular Resistance; D014980:Xenon Radioisotopes
D006626:Hippurates; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D014980:Xenon Radioisotopes; D017263:Technetium Tc 99m Mertiatide; D004369:Pentetic Acid; D012083:Renin; C030514:hippuric acid