Modulation of rat epididymal gamma-glutamyl transpeptidase by nonylphenols.
1. gamma-Glutamyl-transpeptidase (gamma-GTP), present at low levels in the testis, seminal vesicle, prostate gland and epididymis in rat at 4 days of age, showed rapid developmental increases at the time of weaning. 2. Administration of nonylphenols (NP) to the neonatal male rat pup (from days 1 to 15) impaired the subsequent development of gamma-GTP in the epididymis but not in the testis, seminal vesicles or prostate gland. 3. Single injection of NP to weaned pups at approximately 22 days of age decreased gamma-GTP in the epididymis but not in other male accessory sex organs. This effect was transient, dose-dependent and blocked by the oestrogen receptor-specific antagonist ICI 182,780. 4. Single injection of oestradiol to weaned rat at approximately 22 days of age also decreased gamma-GTP in the epididymis but not in the testis, prostate gland or seminal vesicles. 5. In in vitro assays, NP did not inhibit epididymal gamma-GTP activity even at 100 microM final concentration. Under similar conditions, acivicin, a specific inhibitor for gamma-GTP, showed a dose-dependent inhibition of gamma-GTP activity. 6. It is suggested that NP impair gamma-GTP expression in the epididymis of developing male rat and act in part via the oestrogen receptor.
Lee
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Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53226, USA. pclee@mcw.edu
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Jelinek
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Struve
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D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D004822:Epididymis / Q000201:enzymology*; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D007700:Kinetics; D008297:Male; D010636:Phenols / Q000494:pharmacology*; D011467:Prostate / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors; D012669:Seminal Vesicles / Q000201:enzymology; D013737:Testis / Q000201:enzymology; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
D010636:Phenols; D011960:Receptors, Estrogen; D000077267:Fulvestrant; D004958:Estradiol; C025256:nonylphenol; D005723:gamma-Glutamyltransferase