Dexamethasone increases the capacity of urea synthesis time dependently and reduces the body weight of rats.
Rats of 230 g were treated with 0.1 mg of dexamethasone twice daily for 2 days (n = 5) and 14 days (n = 9). Controls received isotonic saline. During the first week of dexamethasone treatment the rats lost weight rapidly (up to 9 g/day). The weight loss diminished during the second week of treatment. The fasting blood insulin concentration increased sevenfold in the dexamethasone-treated rats. Fasting blood glucagon and glucose concentrations were not different from controls. In the dexamethasone-treated rats the fasting alpha-amino-N concentrations were lower: 4.0 +/- 0.3 mmol/l (mean +/- SEM) versus 6.8 +/- 0.3 mmol/l in controls. The capacity of Urea-N Synthesis, determined during alanine loading was: after 2 days of treatment 14.7 +/- 1.7 mumol/(min 100 g), after 14 days of treatment 7.9 +/- 0.8 mumol/(min 100 g), and in controls 7.5 +/- 1.0 mumol/(min 100 g) (mean +/- SEM). In conclusion, glucocorticoid treatment leads to a transient change in the liver function as to hepatic amino-N conversion, implying that more amino-N than normal is eliminated as urea-N after 2 days of treatment. This may contribute to the early, but not the late body weight loss.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001806:Blood Urea Nitrogen; D001835:Body Weight / Q000187:drug effects*; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005934:Glucagon / Q000032:analysis; D007328:Insulin / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014508:Urea / Q000096:biosynthesis*
D001786:Blood Glucose; D007328:Insulin; D003907:Dexamethasone; D014508:Urea; D005934:Glucagon