Feline hyperadrenocorticism (FH) is a rare condition. Pituitary-dependant hyperadrenocorticism (PDH) is observed in approximately 80% of cases. Most of the cases are associated with diabetes mellitus. Diagnosis of FH is quite difficult. First, clinical signs are non specific, except for the non systematic feline skin fragility syndrome. Secondly, the specificity of all tests validated for cats is questionable as well. Recently, an ACTH precursor (POMC/pro-ACTH) assay has been validated in cats (Benchekroun et al. , Proc Am Coll Vet Intern Med (ACVIM) Forum 2008). The aim of this preliminary study is to evaluate prospectively the plasma concentration of ACTH precursors in a small cohort of cats with PDH and estimate its usefulness in its diagnosis. Three groups of cats were defined. Group 1 included cats with PDH. The diagnosis of FH was based on clinical data and low-dose dexamethasone suppression test (LDDST). PDH was demonstrated by adrenal and pituitary gland CT scan. Group 2 and 3 included diabetic and apparently healthy cats respectively. For the two groups, FH was excluded by LDDST or Urine Cortisol:Creatinine Ratio (UCCR). Whole blood was collected from the cats on EDTA-tubes; after immediate centrifugation at 4°C, plasma was promptly frozen (-80°C) until assay. Six cats were included in group 1. 5 cats had a large pituitary tumor with a height ranging from 6 mm to 27 mm. No pituitary tumor was visualised in the remaining cat. Plasma ACTH precursor concentrations ranging from 132 to 1412 pmol/L were measured in PDH cats with large tumors; the remaining cat of group 1 had an ACTH precursor concentration <26 pmol/L. Group 2 and 3 included 8 and 13 cats respectively. Plasma ACTH precursors ranged respectively from <26 to 96 pmol/L and from <26 to 99 pmol/L. Although being found in a small number of cats, these results suggest that large corticotropic tumors are associated in that species with large plasma concentration of ACTH precursors like in dogs. No plasma POMC/pro-ACTH concentration above 100 pmol/L was found in cats free of PDH. The specificity of high plasma ACTH precursor concentration in cats with PDH has to be confirmed on a larger cohort. If confirmed, given the high prevalence of large pituitary tumors, the introduction of this tool could offer a gain of specificity in the general approach of feline PDH.
G. Benchekroun, P. de Fornel Thibaud, M. Dubord, M. Le Chevoir, C. Petit, O. Dossin, et al. (2008). PLASMA ACTH PRECURSORS (PRO-OPIOMELANOCORTIN AND PRO-ADRENOCORTICOTEROPIN) IN CATS WITH HYPERADRENOCORTICISM. GHENT : s.n.
PLASMA ACTH PRECURSORS (PRO-OPIOMELANOCORTIN AND PRO-ADRENOCORTICOTEROPIN) IN CATS WITH HYPERADRENOCORTICISM
FRACASSI, FEDERICO;
2008
Abstract
Feline hyperadrenocorticism (FH) is a rare condition. Pituitary-dependant hyperadrenocorticism (PDH) is observed in approximately 80% of cases. Most of the cases are associated with diabetes mellitus. Diagnosis of FH is quite difficult. First, clinical signs are non specific, except for the non systematic feline skin fragility syndrome. Secondly, the specificity of all tests validated for cats is questionable as well. Recently, an ACTH precursor (POMC/pro-ACTH) assay has been validated in cats (Benchekroun et al. , Proc Am Coll Vet Intern Med (ACVIM) Forum 2008). The aim of this preliminary study is to evaluate prospectively the plasma concentration of ACTH precursors in a small cohort of cats with PDH and estimate its usefulness in its diagnosis. Three groups of cats were defined. Group 1 included cats with PDH. The diagnosis of FH was based on clinical data and low-dose dexamethasone suppression test (LDDST). PDH was demonstrated by adrenal and pituitary gland CT scan. Group 2 and 3 included diabetic and apparently healthy cats respectively. For the two groups, FH was excluded by LDDST or Urine Cortisol:Creatinine Ratio (UCCR). Whole blood was collected from the cats on EDTA-tubes; after immediate centrifugation at 4°C, plasma was promptly frozen (-80°C) until assay. Six cats were included in group 1. 5 cats had a large pituitary tumor with a height ranging from 6 mm to 27 mm. No pituitary tumor was visualised in the remaining cat. Plasma ACTH precursor concentrations ranging from 132 to 1412 pmol/L were measured in PDH cats with large tumors; the remaining cat of group 1 had an ACTH precursor concentration <26 pmol/L. Group 2 and 3 included 8 and 13 cats respectively. Plasma ACTH precursors ranged respectively from <26 to 96 pmol/L and from <26 to 99 pmol/L. Although being found in a small number of cats, these results suggest that large corticotropic tumors are associated in that species with large plasma concentration of ACTH precursors like in dogs. No plasma POMC/pro-ACTH concentration above 100 pmol/L was found in cats free of PDH. The specificity of high plasma ACTH precursor concentration in cats with PDH has to be confirmed on a larger cohort. If confirmed, given the high prevalence of large pituitary tumors, the introduction of this tool could offer a gain of specificity in the general approach of feline PDH.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
