[Diurnal alteration of platelet-free Ca2+ in subjects with normal renal function and patients undergoing CAPD].
We examined the relation of diurnal alteration of platelet-free Ca2+ to blood pressure and plasma vasoactive substances in 6 subjects with normal renal function (N group) (with both normal GFR and normal urine concentration, and with the renal biopsy finding of minor glomerular change) and 7 patients undergoing CAPD (CAPD group), then evaluated the pathophysiological difference in diurnal variations between both groups and the effect of native kidney function. Diurnal values of platelet basal-free Ca2+ concentration in N showed a positive correlation with the corresponding PRA levels. On the other hand, in CAPD they showed a positive correlation with the corresponding levels of plasma AVP. The larger increases in platelet-free Ca2+ concentration due to thrombin stimulation were observed in the daytime and the smaller increases in the nighttime in the N groups. The thrombin-induced changes showed a positive correlation with the diurnal levels of mean blood pressure in N (p < 0.004). However, in contrast, in CAPD the increase in platelet-free Ca2+ due to thrombin tended to be larger in the nighttime and showed a negative correlation with the daily mean blood pressure levels (p < 0.004). These findings suggest that there might be differences in the regulation of intracellular-free Ca2+ dynamics and the diurnal variation between subjects with normal renal function and patients undergoing CAPD. Those differences could affect the progression of vascular disturbance in CAPD patients.
Yamada
K
K
Division of Clinical Research and Internal Medicine, Sakura National Hospital, Chiba, Japan.
Hatakeyama
E
E
Wakabayashi
Y
Y
Nishimura
M
M
Nakano
H
H
Miura
Y
Y
D000328:Adult; D001792:Blood Platelets / Q000737:chemistry*; D001794:Blood Pressure; D002118:Calcium / Q000097:blood*; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory
D002118:Calcium