Oxytocin and Vasopressin Expression in the Ovine Testis and Epididymis: Changes with the Onset of Spermatogenesis1

Abstract

Contractions of seminiferous tubules and epididymal duct walls promote spermiation and sperm transfer, and they are thought to be stimulated by the related peptides oxytocin and vasopressin. This study tested the hypothesis that if oxytocin and/or vasopressin play a physiological role in sperm shedding and transport, then local or circulating concentrations of these peptides would increase during puberty. Testes, epididymides, and trunk blood of sheep at stages during the first spermatogenic wave were collected, and radioimmunoassay measured significant increases in testicular and epididymal oxytocin during spermatogenesis. No changes were measured in circulating oxytocin or in local or circulating vasopressin. Localization and synthesis was investigated by immunohistochemistry and Western blot analysis employing antibodies recognizing epitopes of either oxytocin, oxytocin-associated neurophysin, vasopressin, or vasopressin-associated neurophysin. Marked expression of both oxytocin and its associated neurophysin in testicular Leydig and epididymal principal cells was seen, and weak neurophysin immunoreactivity was also identified in Sertoli cells. The intercellular distribution of oxytocin varied between regions of the epididymis, suggesting several roles for oxytocin. Vasopressin synthesis was not apparent in either tissue. These results confirm the presence and development of paracrine oxytocinergic systems in the ram testis and epididymis of ram during puberty while questioning the physiological importance of vasopressin.

Oxytocin is expressed in epidermal keratinocytes and released upon stimulation with adenosine 5′‐[γ‐thio]triphosphate in vitro

“…To confirm that OT peptide is present in human epidermis and keratinocytes, the OT content of protein extracts from the tissues and cells was measured by EIA (Table S1). The OT content of human epidermis (160 ± 27 pg/g wet weight) was similar to that of sheep testis (60-130 pg/g by radioimmunoassay) (17). These data suggest that both epidermis and cultured keratinocytes synthesize oxytocin peptide.…”

Distribution of oxytocin in the spinal cord and its presence in the peripheral nervous system

“…HPLC-RIA measurements demonstrated that the Gasserian, L5 ganglia and the celiac ganglia of humans contained significant levels of immunoreactive oxytocin ( Table 3, 4). However, our results…”

“…It plays an important role in neuroendocrine regulation of parturition and lactation (Silverman and Zimmerman, 1983;Sofroniew, 1985). Oxytocin is present not only in the hypothalamo-neurohypophyseal system, but is also located in various areas of the central and peripheral nervous system (Buijs, 1978(Buijs, , 1980 Oxytocin may be involved in the local control of androgen biosynthesis and spermatogenesis in the testis (Assinder et al, 2000). The heart and large vessels like aorta and vena cava are also sites of oxytocin synthesis and the locally produced oxytocin may have important regulatory functions within the heart and the vascular system (Gutkowska et al, 2000).…”

Peptidase activities in Crotalus durissus terrificus semen

“…Many peptides, such as angiotensins (Angs; Fraser et al 2006), kinins (Blaukat 2003), substance P, enkephalins (Sastry et al 1991), endorphin (El-Haggar et al 2006), oxytocin (OXT), vasopressin (AVP; Assinder et al 2000), LHRH (Amory & Bremner 2003), TRH, and fertilization-promoting peptide (FPP; Green et al 1996), as well some peptidases, particularly aminopeptidases (APs) and oligopeptidases have been related to seminal physiology in mammals (Fernández et al 2002, Subirán et al 2008. In this sense, Ang I and II are hydrolyzed by acid AP (APA; EC 3.…”