Leptin and leptin receptors in the prostate and seminal vesicles of the adult rat.

Leptin is an adipose tissue-secreted hormone that acts via specific receptors (Ob-R), of which six isoforms are at present recognized (from Ob-Ra to Ob-Rf). Ob-Rb is the only isoform able to activate JAK-STAT and MAPK signaling cascades. A large body of evidence suggests that leptin and its receptors are involved in prostate physiology and pathophysiology in humans, but studies on the leptin system in the rat prostate are lacking. Reverse transcription-polymerase chain reaction showed the expression of mRNAs of leptin, Ob-Ra, Ob-Rb, Ob-Rc, Ob-Re and Ob-Rf in adult rat seminal vesicles and prostate (coagulating, dorsal, ventral and lateral lobes). Western blotting demonstrated the presence in these specimens of the Ob-Rb protein, and immunocytochemistry revealed that Ob-Rb was mainly located in their epithelial-cell component. Collectively, these findings strongly suggest that leptin and Ob-R may be involved in the autocrine-paracrine functional regulation of the epithelial cells of adult rat seminal vesicles and prostate.