Vasopressin secretion in response to osmotic stimulation and effects of desmopressin on urinary concentrating capacity in dogs with pyometra.
OBJECTIVE
To determine vasopressin (VP) secretory capacity during osmotic stimulation and the response to desmopressin treatment in dogs with pyometra and control dogs.


METHODS
6 dogs with pyometra before and after ovariohysterectomy and 6 control dogs.


METHODS
Urine osmolality (Uosm) was measured during 12 hours. Values measured on the first day defined the basal Uosm pattern. On the second day, dogs were given desmopressin to induce a desmopressin-stimulated Uosm pattern. On day 3, the VP response to osmotic stimulation was examined.


RESULTS
Median Uosm on day 1 was 340 mOsm/kg (range, 104 to 1,273 mOsm/kg) and 807 mOsm/kg (range, 362 to 1,688 mOsm/kg) in dogs with pyometra before and after surgery, respectively, and 1,511 mOsm/kg (range, 830 to 1,674 mOsm/kg) in control dogs. Median Uosm during desmopressin treatment was 431 mOsm/kg (range, 168 to 1,491 mOsm/kg) and 1,051 mOsm/kg (range, 489 to 1,051 mOsm/kg) in dogs with pyometra before and after surgery, respectively, and 1,563 mOsm/kg (range, 1,390 to 2,351) in control dogs. In dogs with pyometra, threshold for VP secretion was lower before surgery (median, 340 mOsm/kg; range, 331 to 366 mOsm/kg) than after surgery (median, 358 mOsm/kg; range, 343 to 439 mOsm/kg) or in control dogs (median, 347 mOsm/kg; range, 334 to 360 mOsm/kg). Highest maximum plasma VP values were found in dogs with pyometra.


CONCLUSIONS
Dogs with pyometra had increased urine concentration in response to desmopressin but not to the degree of control dogs, whereas VP secretory ability was not reduced.
Heiene
Reidun
R
Department of Companion Animal Clinical Sciences, Norwegian School of Veterinary Science, PO Box 8146 dep, 0033 Oslo, Norway.
van Vonderen
Ilse K
IK
Moe
Lars
L
Mølmen
Guro S
GS
Larsen
Nina H
NH
Kooistra
Hans S
HS
D000818:Animals; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology*; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D004653:Empyema / Q000662:veterinary*; D005260:Female; D007044:Hysterectomy / Q000662:veterinary; D007671:Kidney Concentrating Ability / Q000187:drug effects*; D009994:Osmolar Concentration; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D014591:Uterine Diseases / Q000662:veterinary*; D014667:Vasopressins / Q000097:blood / Q000187:drug effects / Q000378:metabolism*
D012462:Saline Solution, Hypertonic; D014667:Vasopressins; D003894:Deamino Arginine Vasopressin