Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxytocin is present in the mammalian testis where it increases contractility of seminiferous tubules in vitro and has been implicated in sperm transport. The present study investigated whether oxytocin affects the transport of spermatozoa from the testis in vivo. In rats, mature spermatozoa are first seen in the testis 42 days postpartum and arrive in the epididymis at about day 45. Male Wistar rats were given daily subcutaneous injections of either oxytocin (0.5 micrograms), the oxytocin antagonist des Gly-NH2d(CH2)5-[D-Tyr2,Thr4]OVT (0.2 micrograms) or saline from day 40 postpartum. Groups of six animals were killed 2 h after their last injection on days 43, 44, 45 and 46 postpartum. Testes were removed and fixed in Bouin's fluid for histological examination and the number of spermatozoa in the epididymides was counted. Spermatozoa were seen in the epididymis earlier in the oxytocin-treated rats (day 43) than in the control animals (day 44), and treatment with the antagonist delayed the appearance of spermatozoa in the epididymis until day 45. When the testes were examined, residual bodies, which were used as an indicator of spermiation, were seen only in one control animal before day 44. Residual bodies were seen in the testes of all oxytocin-treated rats on day 43 but were not detected until day 45 in the oxytocin antagonist-treated rats. These data show that in rats oxytocin can affect the arrival of spermatozoa in the epididymis. Although this may be due in part to effects on tubal transport or the secretion of tubular fluid, these findings suggest that the peptide may affect spermiation.
 ...
PMID:Effects of oxytocin on sperm transport in the pubertal rat. 888 97

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.
 ...
PMID:Oxytocin and vasopressin expression in the ovine testis and epididymis: changes with the onset of spermatogenesis. 1090 49