Acth ZVND B-Endorphin-Related Peptides Are Present in Multiple Sites in the Reproductive Tract of the Male Rat

Regulation of Male Fertility by the Opioid System

“…However, the small POMC transcript in pachytene spermatozoa was found to be inefficiently transcribed during spermatogenesis (46). These findings are consistent with the detection of β-endorphin immunoreactivity in Leydig cells in many species (37). The synthesis of β-endorphin is controlled by LH secreted by the pituitary in adult rats (52) and also by corticotropin-releasing factor (CRF).…”

“…Numerous studies have demonstrated the presence of EOPs in different testicular cell types (35)(36)(37). In addition, binding studies have revealed the presence of all three types of opioid receptors (DOR, MOR and KOR) in rat testes.…”

“…Thus, EOPs are mainly synthesized de novo by Leydig cells in the testis, although EOPs have no effect on testosterone production in cultured Leydig cells or in rat testicular tissue after human chorionic gonadotropin (hCG) treatment (37,57). However, intratesticular administration to rats of the opioid antagonist naloxone and nalmefene was found to decrease basal secretion of testosterone and reduce levels of serum testosterone (58).…”

Action of proteolytic enzymes on lipotropins and endorphins: Biosynthesis, biotransformation and fate

“…Subsequently, several reports have indicated indirectly the presence of ~t-and 7-endorphins in pituitary tissue by detecting peptides with opiate-like properties of the size of these/~-endorphin fragments (Giagnoni et al, 1977;Sabol, 1978;Lissitsky et al, 1978). Peptides related to ct-and 7-endorphin have been immunologically and/or chromatographically characterized in extracts of rat anterior and intermediate pituitary (Jegou et al, 1978(Jegou et al, , 1979Fukata et al, 1979;Verhoef et al, 1980aVerhoef et al, ,b, 1982Dorsa et al, 1982;Wiegant et al, 1983a,b), in rat brain (Verhoef et al, 1980(Verhoef et al, , 1982aDorsa et al, 1981;Wiegant et al, 1983a,b), in human pituitary and brain (Burbach and Wiegant, 1983; unpublished observations), in guinea pig myenteric plexus (Opmeer et al, 1980), and in rat testicular tissue (Tsong et al, 1982;Shu-Dong et al, 1982;Margioris et al, 1983). Immunohistochemical localization studies have shown the storage of ct-endorphin and 7-endorphins in pituitary and rat brain (B6geot et al, 1978;Vaudry et al, 1980).…”

Effects of a Met-Enkephalin Analogue on motility, O2Consumption, and ATP Content of Human Spermatozoa

“…Immunostainable ACTH and betaendorphin, in particular, have been observed in the cytoplasma of the Leydig cells and in the epithelium of the epididymis, seminal vesicle, and rat vas deferens [14]. The source and the physiological role of these opioid peptides in the reproductive tract are still unknown.…”