Open AccessPolyuria and Polydipsia and Disturbed Vasopressin Release in 2 Dogs With Secondary Polycythemia
Author(s) -
Vonderen Ilse K.,
Meyer Hein P.,
Kraus Johannes S.,
Kooistra Hans S.
Publication year - 1997
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.1997.tb00469.x
Subject(s) - polyuria , polydipsia , medicine , vasopressin , hypertonic saline , plasma osmolality , endocrinology , urine osmolality , thirst , diabetes mellitus
In dogs, secondary polycythemia (SP) may be associated with polyuria and polydipsia (PU/PD). The pathogenesis of this PU/PD has not yet been explained. We hypothesized that hyperviscosity and increased blood volume in SP might affect vasopressin (VP) release, resulting in PU/PD. This hypothesis was tested in 2 dogs with SP caused by renal neo‐plasia and PU/PD. Osmoregulation of VP release was studied by a modified water deprivation test and by investigating the VP response to hypertonic saline infusion. Water deprivation test results were consistent with an inability to produce concentrated urine despite increasing plasma osmolality. During hypertonic saline infusion, the osmotic threshold of VP release was markedly increased in both dogs, resulting in a delayed VP response to increasing plasma osmolality. The sensitivity of VP release was low normal in both dogs. We conclude that blood hyperviscosity and increased blood volume led to impaired VP release and polyuria.