Parathyroid hormone and platelet cytosolic calcium concentration in essential hypertension.
To investigate the possible relationships between blood pressure, parathyroid hormone (PTH) and platelet cytosolic Ca2+ concentration ([Ca2+]i) in patients with essential hypertension, we studied 17 patients with this disease aged 48 +/- 2 years and 17 normotensive controls aged 44 +/- 3 years. Platelet [Ca2+]i was measured by spectrofluorimetry using the dye Fura-2 acetoxymethylester. Patients with essential hypertension displayed lower levels of serum ionized Ca2+ (0.99 +/- 0.03 versus 1.1 +/- 0.01 mmol/l, P < 0.05) and higher serum intact PTH levels (37 +/- 3 versus 26 +/- pg/ml, (P < 0.01) than the normotensive controls. Although serum levels of intact PTH were significantly correlated with mean arterial pressure (MAP) in the combined group of subjects (r = 0.42, P < 0.05), there was no correlation when each group was considered separately. Resting platelet [Ca2+]i was also higher in patients than in controls (57 +/- 3 versus 48 +/- 2 nmol/l, P < 0.005). When platelets were stimulated in vitro with thrombin, the increment in [Ca2+]i was also greater in patients than in controls in the presence of extracellular Ca2+ (264 +/- 24 versus 194 +/- 19 nmol/l, P < 0.05) but not in its absence (123 +/- 12 versus 112 +/- 10 nmol/l). The thrombin-induced increment in [Ca2+]i was correlated with MAP in the hypertensive patients (r = 0.64, P < 0.01) and in the combined group of subjects (r = 0.42, P < 0.05). There was no relationship between resting or thrombin-induced [Ca2+]i and serum PTH in either group of patients or in the combined group of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
Poch
E
E
Nephrology Service, Hospital Clinic I Provincial, University of Barcelona, Catalonia, Spain.
Fernández-Llama
P
P
Botey
A
A
Gaya
J
J
Darnell
A
A
Rivera
F
F
Revert
L
L
D000328:Adult; D001792:Blood Platelets / Q000737:chemistry*; D001794:Blood Pressure; D002118:Calcium / Q000097:blood*; D003600:Cytosol / Q000737:chemistry; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D015539:Platelet Activation / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013917:Thrombin / Q000494:pharmacology
D010281:Parathyroid Hormone; D013917:Thrombin; D002118:Calcium