EXPRESSION OF cAMP AND CREB IN THE HUMAN PENIS 

The aim of this study is to investigate the expression of adenosine 3',5'-cyclic monophosphate (cAMP) and cAMP-response element-binding protein (CREB) in the human penis as it is known that luteinizing hor-mone (LH) regulates cellular function mostly through the cAMP signaling pathway and LH receptors are expressed by the penile endothelium. Penile tissue was obtained from three patients during partial or total penectomy due to a rectal cancer with secondary penile metastasis or squamous cell carcinoma of the penis. Immunohistochemistry was used for the detection of cAMP and CREB. Positive immunoreaction for cAMP was present in most cells of superficial, intermedial, and basal layer of urethral epithelium and in fibroblast-like cells (FLC) of interstitial tissue and endothelial cells (EC) of cavernous spaces in corpus spongiosum penis. Positive staining for cAMP was also visible in EC of cavernous spaces and in FLC of interstitial tissue in corpus cavernosum penis. Positive immunoreaction for CREB was present in the super-ficial and intermedial layer of urethral epithelium, and some positive immunoreaction was also noticed in EC of cavernous spaces and in FLC of interstitial tissue in corpus spongiosum penis. Positive staining was also visible in the EC of cavernous spaces and in fibroplast-like cells of the interstitial tissue in the corpus cavernosum penis. Our results show the presence of cAMP and CREB in the human penis. While LH exerts its actions through cAMP signaling system and our previous studies have shown the expression of lutein-izing hormone/choriogonadotropin (LHCG) receptor in the mouse and human penis, this finding may support the hypothesis that LH could affect the spongious and cavernous tissue of the human penis and thereby influence the development of erectile dysfunction among aging men.

cAMP; corpus cavernosum penis; corpus spongiosum penis; CREB; erectile disturbances; luteinizing hormone

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