Location of a membrane-bound carbonic anhydrase isoenzyme (CA IV) in the human male reproductive tract

• Published in: The journal of histochemistry and cytochemistry Vol. 41; no. 5; pp. 751 - 757
• Main Authors: Parkkila, S, Parkkila, AK, Kaunisto, K, Waheed, A, Sly, WS, Rajaniemi, H
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA Histochemical Soc 01.05.1993; SAGE Publications; Histochemical Society
• Subjects: Biological and medical sciences; Blotting, Western; Carbonic Anhydrases - analysis; Cell Membrane - enzymology; Epididymis - enzymology; Fundamental and applied biological sciences. Psychology; Humans; Male; Mammalian male genital system; Morphology. Physiology; Prostate - enzymology; Testis - enzymology; Vertebrates: reproduction; Human; Epididymis; Spermatozoa; Enzymatic activity; Carbonic anhydrase; Seminal vesicle; Enzyme; Localization; Male genital system
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/41.5.8468457

We studied the location of a membrane-bound carbonic anhydrase (CA IV) in the human male reproductive tract using a specific antiserum to human CA IV in conjunction with immunoblotting, immunoperoxidase, and immunofluorescence techniques. The microvilli and apical plasma membrane of the epithelial cells and the subepithelial smooth muscle layer of the epididymis, ductus deferens, and ampulla of the ductus deferens showed specific staining for CA IV. The epithelial cells of the prostate and seminal vesicle failed to stain for CA IV, however, whereas the subepithelial smooth muscle layer showed positive staining. No specific staining for CA II was seen in the epithelium of the epididymal duct or the proximal ductus deferens. The presence of CA IV in the epididymis was confirmed by immunoblotting, which revealed 35 KD and 33 KD polypeptides. The results show that the microvilli and the apical plasma membrane of the lining epithelium of the epididymal duct, ductus deferens, and ampulla of the ductus deferens contain the membrane-bound carbonic anhydrase isoenzyme IV. The presence of the enzyme in the epithelium of the epididymis and ductus deferens is probably linked to the acidification of the epididymal fluid that prevents premature sperm activation. Its physiological role in the smooth muscle cells remains to be elucidated.