Changes in serum dehydroepiandrosterone, androstenedione, testosterone, and 17β-oestradiol levels associated with disease and surgery in the horse

Abstract

The aim of this work was to measure serum concentrations of dehydroepiandrosterone, androstenedione, testosterone and 17β-oestradiol in horses with various diseases and after surgery. We hypothesize that diseases and castration could potentially affect concentrations of steroid reproductive hormones. Blood samples were obtained from six groups of horses comprising a total of 119 horses (75 males and 44 females, 5–15 years old) with laminitis, acute abdominal syndrome, acute diseases, chronic diseases, after castration and healthy control. Hormone concentrations in serum were determined for each group using competitive enzyme immunoassay. Significant increases compared to control were found for dehydroepiandrosterone in horses with castration (P < 0.01), acute abdominal syndrome and acute diseases (P < 0.05). Besides, significant increases were observed for androstenedione in horses with laminitis, castration and acute diseases (P < 0.01), and in acute abdominal syndrome and chronic diseases (P < 0.05). Significant increases were also found for testosterone in horses with castration (P < 0.01) and with laminitis, acute abdominal syndrome and chronic diseases (P < 0.05). The lowest values of testosterone were found in the control group. Compared to control, 17b-oestradiol serum concentrations showed significant decreases (P < 0.01) in horses with laminitis, acute abdominal syndrome, acute and chronic diseases. Significant differences (P < 0.05) for the four studied hormones were found between males and females in each group. Our results showed that there were significant differences in steroid reproductive hormone concentrations in diseased horses and in those after surgery, compared to controls.