[Relationship between plasma level of leptin and the expression of leptin receptor in human adrenal tissues and tumors].

OBJECTIVE

To compare the mRNA, protein expression of long leptin receptor (Ob-Rb) in human adrenal tissues and tumors and observe the plasma level of leptin in primary aldosteronism (PA), cortisol-secreting tumors (CS) and pheochromocytomas (PHEO).

METHODS

Total RNA and protein were extracted from 6 normal human adrenal glands, 10 CS, 20 PHEO; and 14 aldosterone-producing adenomas (APA) (RNA), 10 APA (protein); plasma samples were drawn from 20 controls, 15 PHEO, 29 PA and 11 CS.

RESULTS

The mRNA and protein of Ob-Rb were widely expressed in human adrenal glands and tumors. The mRNA (0.32±0.12) and protein (1.31±0.26) expressions of Ob-Rb were higher in normal human adrenal cortex (C) than all other tissues (P<0.05) while the mRNA expression of Ob-Rb in APA (0.15±0.10) was higher than CS (0.05±0.02) (P<0.05). The mRNA expression of Ob-Rb in APA was positively correlated with plasma supine aldosterone level (r=0.670, P=0.024). The mRNA expression of Ob-Rb in CS was positively correlated with 24-hour urinary free cortisol level (r=0.870, P=0.005). The plasma level of leptin was higher in CS than in non-CS groups (P=0.001).

CONCLUSIONS

Ob-Rb is widely expressed in adrenal tissues and tumors. There is a differential expression in various tissues. Further studies are warranted to understand the relationship between leptin and adrenal gland.