Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.21 (CPT)
 4,580 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Single rat epididymal cell studied under whole cell patch-clamp condition responded to 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPT-cAMP) (500 microM) and to ionomycin (1 microM) by an increase in whole cell conductance. A major part of the stimulated current was carried by Cl-, although a small part was due to nonselective cation current. After elimination of the cation current component by using impermeant cation, the cells revealed different Cl- conductance properties in response to adenosine 3',5'-cyclic monophosphate (cAMP) and ionomycin. The cAMP-stimulated Cl- conductance was independent of time and voltage and showed a linear current-voltage relationship. The anion permselectivity was NO3- > Br- > Cl- approximately I- >> SO(4)2-. The ionomycin-stimulated Cl- conductance showed marked time and voltage dependency. In contrast to the cAMP-induced anion permselectivity, the ionomycin-induced anion permselectivity was I- > Br- approximately NO3- > Cl- >> SO(4)2-. These results indicate that the epididymal epithelial cells exhibit different Cl- conductances sensitive to cAMP and Ca2+. The cAMP-activated conductance has properties resembling the type associated with the cystic fibrosis transmembrane conductance regulator found in cystic fibrosis-affected epithelia. This finding supports the notion that the epididymis is a cystic fibrosis epithelium.
 ...
PMID:Properties of cAMP-dependent and Ca(2+)-dependent whole cell Cl- conductances in rat epididymal cells. 768 72

l-carnitine has a documented role as a cofactor in cellular energy metabolism and fatty acid beta-oxidation pathways and it has also been considered to function in reproductive biology. We investigated whether decreasing concentrations of L-carnitine using an inhibitor of its biosynthesis, mildronate (3-(2,2,2-trimethylhydrazinium)-propionate), would influence the sexual behavior or sperm quality in male rats. Mildronate treatment induced a significant decrease in carnitine concentration and an increase in gamma-butyrobetaine (GBB) concentration in both plasma and testes extracts. However, the expression of carnitine palmitoyltransferase I in testes and testosterone concentration in plasma was not changed in mildronate treated rat. Behavioral experiments demonstrated that mildronate treatment did not decrease the sexual motivation in both sexually naive and sexually experienced rats. The densities of spermatozoa in the cauda epididymis, as well as motility, were unchanged after mildronate treatment at a dose of 100 mg/kg. In conclusion, our study provides experimental evidence that mildronate induces decrease in the free carnitine concentration in rat testes, but does not decrease the sexual activity or sperm quality of male rats.
 ...
PMID:Effect of inhibiting carnitine biosynthesis on male rat sexual performance. 1864 Jan 37

We examined the rat and mouse epididymis using helium ion microscopy (HIM), a novel imaging technology that uses a scanning beam of He(+) ions to produce nanometer resolution images of uncoated biological samples. Various tissue fixation, sectioning and dehydration methods were evaluated for their ability to preserve tissue architecture. The cauda epididymidis was luminally perfused in vivo to remove most spermatozoa and the apical surface of the epithelial lining was exposed. Fixed epididymis samples were then subjected to critical point drying (CPD) and HIM. Apical stereocilia in principal cells and smaller apical membrane extensions in clear cells were clearly distinguishable in both rat and mouse epididymis using this technology. After perfusion with an activating solution containing CPT-cAMP, a permeant analog of cAMP, clear cells exhibited an increase in the number and size of membrane ruffles or microplicae. In contrast, principal cells did not exhibit detectable structural modifications. High-resolution HIM imaging clearly showed the ultrastructure of residual sperm cells, including the presence of concentric rings on the midpiece, and of cytoplasmic droplets in some spermatozoa. Close epithelium-sperm interactions were also detected. We found a number of sperm cells whose heads were anchored within the epididymal epithelium. In certain cases, the surface of the sperm cytoplasmic droplet was covered with vesicle-like structures whose size is consistent with that of epididymosomes. In conclusion, we describe here the first application of HIM technology to the study of the structure and morphology of the rodent epididymis. HIM technology represents a major imaging breakthrough that can be successfully applied to study the epididymis and spermatozoa, with the goal of advancing our understanding of their structure and function.
 ...
PMID:High-resolution helium ion microscopy of epididymal epithelial cells and their interaction with spermatozoa. 2501 75