Paulin Mathieu Victor, Mehrabanpour Dorsa, Unniappan Suraj, Snead Elisabeth C R
Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
J Vet Intern Med. 2025 Jan-Feb;39(1):e17304. doi: 10.1111/jvim.17304.
The pathophysiology of polyuria and polydipsia secondary to exogenous glucocorticoid excess is incompletely understood.
Investigate plasma AVP (pAVP) and serum CoP (sCoP) concentrations in healthy dogs before, during, and after abrupt discontinuation of a long-term course of orally administered prednisolone.
Eight healthy neutered young adult research Beagles.
In our prospective longitudinal study, Beagles were treated with a placebo PO q24h for 15 days (baseline), followed by a 35-day course of prednisolone (2.35-2.75 mg/kg PO q24h) and then abrupt discontinuation of prednisolone. Serial pAVP and sCoP concentrations, urine specific gravity (USG) and calculated plasma osmolality (pOsm) were determined during placebo and prednisolone administration, and up to 4 weeks after prednisolone discontinuation. Paired plasma samples for pAVP measurement were obtained in EDTA tubes with (pAVP) and without (pAVP) a proprietary combination of protease, esterase, and dipeptidyl peptidase-IV inhibitors (BD Biosciences P800).
Mean pAVP and sCoP concentrations were significantly lower at the end of the prednisolone course (25.8 ± 8.1 pg/mL and 166 pg/mL, range, 131-223) vs baseline (34.1 ± 5.4 pg/mL and 243 pg/mL, range, 157-336; P = .02, P = .02, respectively). Correlations between pAVP and sCoP (r = .77, P = .001) and pAVP and USG (r = .61, P = .02) were positive, despite no correlation between pAVP and pOsm, sCoP and pOsm, and sCoP and USG. On paired samples, mean pAVP was significantly lower (5.0 ± 2.5 pg/mL) than mean pAVP (34.1 ± 5.4 pg/mL; P < .0001).
Orally administered prednisolone led to markedly decreased plasma AVP and serum CoP concentrations despite increased calculated plasma osmolality and stable systolic blood pressure.
外源性糖皮质激素过量继发的多尿和烦渴的病理生理学尚未完全明确。
研究健康犬在口服泼尼松龙长期疗程开始前、期间和突然停药后血浆血管加压素（pAVP）和血清皮质醇结合蛋白（sCoP）浓度。
8只健康去势的年轻成年实验用比格犬。
在我们的前瞻性纵向研究中，比格犬每天口服安慰剂24小时，共15天（基线期），随后进行35天的泼尼松龙疗程（2.35 - 2.75毫克/千克，每天口服一次），然后突然停用泼尼松龙。在服用安慰剂和泼尼松龙期间以及停用泼尼松龙后长达4周内，测定连续的pAVP和sCoP浓度、尿比重（USG）和计算得出的血浆渗透压（pOsm）。用于pAVP测量的配对血浆样本在含有（pAVP）和不含有（pAVP）蛋白酶、酯酶和二肽基肽酶 - IV抑制剂专有组合（BD Biosciences P800）的EDTA管中采集。
泼尼松龙疗程结束时，平均pAVP和sCoP浓度（分别为25.8±8.1皮克/毫升和166皮克/毫升，范围为131 - 223）显著低于基线期（分别为34.1±5.4皮克/毫升和243皮克/毫升，范围为157 - 336；P = 0.02，P = 0.02）。尽管pAVP与pOsm、sCoP与pOsm以及sCoP与USG之间无相关性，但pAVP与sCoP（r = 0.77，P = 0.001）以及pAVP与USG（r = 0.61，P = 0.02）之间呈正相关。在配对样本中，平均pAVP（5.0±2.5皮克/毫升）显著低于平均pAVP（34.1±5.4皮克/毫升；P < 0.0001）。
尽管计算得出的血浆渗透压升高且收缩压稳定，但口服泼尼松龙导致血浆AVP和血清CoP浓度显著降低。
