Lipostat in the lean rat: evidence for a non-causal relationship between glucocorticoids and leptin levels

In order to assess the long-term impact of a complete depletion of glucocor ticoids on plasma leptin levels, we bilaterally adrenalectomized 20 lean ra ts, and analysed glucocorticoids and leptin levels for 20 consecutive days. Results demonstrate that the adrenalectomy (ADX) significantly lowered the leptin levels, as compared to sham-operated controls. On the other hand, a significant increase in leptin levels was noticeable from day 1 to day 20 of the experiment in the sham-operated controls, even though corticosterone levers remained stable during that same period. Plasma leptin concentratio n was proportional to body fat content. These results would indicate a non- causal relationship between glucocorticoids and leptin levers in the contex t of a lipostat in the lean rat. (C) 2000 Academic Press.