ABSTRACT
Despite the European ban on the use of growth promoters in cattle, veterinary surveillance reports indicate that the illicit use of corticosteroids persists both alone and in combination with anabolic hormones and ß-agonists. Current control strategies should be informed by research into the effects of corticosteroids on bovine metabolism and improved through the development of specific, sensitive diagnostic methods that utilize potential molecular biomarkers of corticosteroid treatment. The actions of corticosteroids on target tissues are principally regulated by two receptors: the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). The effects of these steroids are modulated by prereceptor enzyme-mediated metabolism: the two isoforms of the 11ß-hydroxysteroid dehydrogenase (11ß-HSDs) enzyme catalyze the interconversion between active glucocorticoids, such as cortisol, into inactive compounds, such as cortisone. This study aimed to determine whether the expression of the prereceptor system and of the corticosteroid receptors could be regulated in different target tissues by the administration of dexamethasone and prednisolone in cattle. It was observed that greater up-regulation of the GR and MR genes followed dexamethasone treatment in the muscle tissues than in the kidney, liver, and salivary glands; up-regulation of GR and MR expression following prednisolone treatment was higher in adipose tissue than in the other tissues. The thymus seemed to respond to dexamethasone treatment but not to prednisolone treatment. Both treatments significantly down-regulated 11ß-HSD2 gene expression in the adrenal tissues, but only dexamethasone treatment down-regulated 11ß-HSD2 expression in the bulbourethral and prostate glands. Together, these data indicate that the combination of GR, MR, and 11ß-HSD2 could provide a useful biomarker system to detect the use of illicit glucocorticoid treatment in cattle.
Subject(s)
Biomarkers/analysis , Glucocorticoids/administration & dosage , Meat/analysis , Receptors, Steroid , Substance Abuse Detection/veterinary , 11-beta-Hydroxysteroid Dehydrogenase Type 2/genetics , Adipose Tissue/metabolism , Animals , Cattle , Dexamethasone/administration & dosage , Male , Muscles/metabolism , Polymerase Chain Reaction/veterinary , Prednisolone/administration & dosage , Receptors, Glucocorticoid/genetics , Receptors, Mineralocorticoid/genetics , Substance Abuse Detection/methods , Up-Regulation/drug effects , Veterinary DrugsABSTRACT
In this report a 9-year-old female German Shepherd dog with a membranoproliferative glomerulonephritis (MPGN) type III associated with concomitant infection of Dirofilaria immitis and Leishmania infantum is presented. Light microscopic evaluation of kidney revealed a diffuse hypercellularity and thickening of glomerular basement membrane. Heavy and coarse granular complement C(3) deposition and a weaker positive reaction to immunoglobulin G were present along peripheral glomerular basement membrane and in the mesangium in the immunofluorescent study. Transmission electron microscopy revealed deposits in the mesangium, subendothelium, and subepithelium. These lesions are compatible with membranoproliferative glomerulonephritis type III in humans.
