Expression of the receptor guanylyl cyclase C and its ligands in reproductive tissues of the rat: A potential role for a novel signaling pathway in the epididymis

Guanylyl cyclase C (GC-C) is a membrane-associated form of guanylyl cyclase and serves as the receptor for the heat-stable enterotoxin (ST) peptide and endogenous ligands guanylin, uroguanylin, and lymphoguanylin. The major site of expression of GC-C is the intestinal epithelial cell, although GC-C is also expressed in extraintestinal tissue such as the kidney, airway epithelium, perinatal liver, stomach, brain, and adrenal glands. Binding of ligands to GC-C leads to accumulation of intracellular cGMP, the activation of protein kinases G and A, and phosphorylation of the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel that regulates salt and water secretion. We examined the expression of GC-C and its ligands in various tissues of the reproductive tract of the rat. Using reverse transcriptase and the polymerase chain reaction, we demonstrated the presence of GC-C, uroguanylin, and guanylin mRNA in both male and female reproductive organs. Western blot analysis using a monoclonal antibody to GC-C revealed the presence of differentially glycosylated forms of GC-C in the caput and cauda epididymis. Exogenous addition of uroguanylin to minced epididymal tissue resulted in cGMP accumulation, suggesting an autocrine or endocrine activation of GC-C in this tissue. Immunohistochemical analyses demonstrated expression of GC-C in the tubular epithelial cells of both the caput epididymis and cauda epididymis. Our results suggest that the GC-C signaling pathway could converge on CFTR in the epididymis and perhaps control fluid and ion balance for optimal sperm maturation and storage in this tissue.

Potential histopathological and molecular changes in rat vas deferens inhaled by Boswellia papyrifera and Boswellia carterii

Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4g/kg body weight B. papyrifera and B. carterii daily for 120days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens.