Effect of prednisolone on thyroid and gonadotrophic hormones secretion in male domestic rabbits

Abstract

Context: An excess of endogenous and exogenous glucocorticoids causes many biochemical endocrine effects. Such alterations resulted in erroneous misleading interpretation of laboratory results. Aims: The effect of six intramuscular (I/M) injections of prednisolone on the serum concentrations of thyroxin (T 4 ), triiodothyronine (T 3 ), thyroid stimulating hormone (TSH), and luteinizing hormone (LH) of male domestic rabbits was assessed. Materials and Methods: Ten rabbits were assigned into two equal groups, treated and control groups. The treated group was injected prednisolone 1% at a rate of 2.2 mg/kg body weight every other day for a total of six doses. The control group was injected I/M with an equivalent volume of vehicle solution of prednisolone 1%. Statistical Analysis: All data were presented as mean ± standard error of mean by Student's t-test. All tests were performed using the Statistical Package for Social Science Program. Results: At day 6 of the experiment (after three injections of prednisolone), there were nonsignificant differences (P > 0.5) in serum T 4 , T 3 and TSH concentrations in prednisolone-treated animals compare to control. However, the concentration of serum LH was decreased significantly (P 0.5) in the concentration of TSH in prednisolone-treated animals compare to control whereas the concentrations of serum T 4 , T 3 and LH were decreased significantly (P < 0.5) in prednisolone-treated animals compare to control. Conclusion: Multiple administration of prednisolone was clearly associated with substantial reduction in the concentrations of T 4 and T 3 and reduction of LH concentration without any effect on TSH concentration in serum of domestic rabbits.