Platelet vasopressin receptors in patients with congenital nephrogenic diabetes insipidus.
Arginine-vasopressin (AVP), interacts with at least two types of receptors: V1 receptors which mediate the aggregating effects of AVP on human blood platelets and other AVP actions on vascular smooth muscle and hepatocytes; and V2 receptors which mediate the antidiuretic effects on renal tubules. Congenital nephrogenic diabetes insipidus (CNDI) is a rare X-linked disorder in humans with abnormal renal and extrarenal V2-receptor responses. However, the V1 receptor responses are apparently normal, since in these patients blood pressure increases in response to AVP. To assess V1 receptor responses, binding studies (3H-AVP) were done on intact platelets obtained from 6 male patients with CNDI, 10 normal subjects and 4 patients with autosomal dominant central diabetes insipidus (ADCDI). The affinity constant (0.68 +/- 0.04 vs. 0.59 +/- 0.06 nM) and the number of specific binding sites per platelet (101 +/- 6 vs. 86 +/- 12) were similar in the normal subjects and the patients with CNDI. However, the number of binding sites per platelet was increased in the patients with ADCDI (189 +/- 12). Platelet aggregation induced by AVP was equivalent in the three groups. Platelet-fraction AVP was elevated in patients with CNDI and undetectable in patients with ADCDI. These results suggest that the structure and the function of V1 platelet receptor-effector pathway are normal in patients with CNDI.
Bichet
D G
DG
Service de néphrologie, Hôpital du Sacré-Coeur de Montréal, Canada.
Arthus
M F
MF
Lonergan
M
M
D000293:Adolescent; D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism*; D002648:Child; D003919:Diabetes Insipidus / Q000097:blood* / Q000150:complications / Q000151:congenital; D006801:Humans; D066298:In Vitro Techniques; D007674:Kidney Diseases / Q000097:blood* / Q000150:complications / Q000151:congenital; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D011945:Receptors, Angiotensin / Q000378:metabolism*; D017483:Receptors, Vasopressin; D014867:Water / Q000008:administration & dosage
D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014867:Water; D001127:Arginine Vasopressin