Endocrine-paracrine cells of the male urogenital apparatus: a comparative histochemical and immunohistochemical study in some domestic ungulates.

This research article focused on studying endocrine and paracrine cells within the male urogenital system of various large domestic animals, specifically boars, bulls, horses, and donkeys.

Research Methods

• This study utilized specimens of the testis, the excurrent duct, male accessory glands, and urinary tract from different large domestic animals: boars, bulls, horses, and donkeys.
• Two main histochemical methods were applied: Silver impregnation, which is used to visualize certain types of cells, and immunohistochemistry, a method that uses antibodies to detect specific proteins and other substances in cells. These approaches helped identify the presence and location of endocrine and paracrine cells.
• Immunoreactivity tests for chromogranin A, 5-hydroxytryptamine, somatostatin, [met]-, [leu]- enkephalins, gastrin-releasing peptide, calcitonin gene-related peptide, neuropeptide Y, substance P, vasoactive intestinal peptide, beta-endorphin antisera were conducted using the streptavidin-biotin technique.

Research Findings

• Endocrine cells were not found within the testis, epididymis, ductus deferens, or vesicular gland on any of the animals studied.
• Cells showing chromogranin-A, serotonin, somatostatin, and enkephalins were detected on the surface or within glandular epithelia. Other tested antisera gave negative results, meaning that their presence could not be confirmed.
• In the prostatic complex and the urethral epithelium, serotonin-immunoreactive endocrine cells were most prevalent. Few cells demonstrated argentaffinity, and a limited number showed argyrophily and chromogranin-A immunoreactivity.
• Cells showing reactivity to somatostatin and enkephalins were rare in bulls and boars, and completely absent in horses.

Conclusion

• This study showed profound differences in the immunophenotype of endocrine and paracrine cells between different species of domestic ungulates, even those closely related like horses and donkeys.
• This may be significant in understanding the variance in reproductive physiology across different species.