title: Human sperm physiology: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) influence sperm metabolism and may be involved in the pathophysiology of varicocele-associated male infertility.
abstract: The mechanisms by which varicocele affects fertility remain undetermined. Estrogens play a key role in the human male reproduction and human sperm expresses the estrogen receptors (ERs) and aromatase. In this study, by Western blotting we evidenced the ERs content concomitantly in healthy sperm and in oligoastenoteratozoospermic (OAT) samples without and with varicocele. In varicocele a strong reduction of the ERβ was observed, while the ERα was almost absent. Besides, transmission electron microscopy (TEM) confirmed the reduction of ERs expression in "varicocele" sperm, indicating that varicocele has a detrimental effect on sperm structure at molecular level. To further define the estrogen significance in male gamete and the pathophysiology of varicocele we investigated both the expression of ERα and ERβ in normal and pathologic sperm samples as well as we evaluated estradiol (E2) action on lipid and glucose sperm metabolism. Responses to E2 treatments on cholesterol efflux, protein tyrosine phosphorylations, motility, and acrosin activity in varicocele sperm were reduced or absent. The evaluation of the triglycerides content, lipase and acyl-CoA dehydrogenase activities, suggest that E2 exerts a lipolytic effect on human sperm metabolism. Concerning glucose metabolism, it appears that E2 induces G6PDH activity concomitantly to the insulin secretion. In "varicocele" sperm, the E2 did not induce energy expenditure. OAT sperm had E2-responsiveness but in a lesser extent with respect healthy sperm. This study discovered a novel role for E2/ERs in human sperm physiology, since they modulate sperm metabolism and new detrimental effects related to the pathophysiology of the varicocele condition.
authors.affiliation: Centro Sanitario, University of Calabria, Cosenza, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Guido
authors.forename: Ida
authors.initials: I
authors.lastname: Perrotta
authors.forename: Salvatore
authors.initials: S
authors.lastname: Panza
authors.forename: Emilia
authors.initials: E
authors.lastname: Middea
authors.forename: Paola
authors.initials: P
authors.lastname: Avena
authors.forename: Marta
authors.initials: M
authors.lastname: Santoro
authors.forename: Stefania
authors.initials: S
authors.lastname: Marsico
authors.forename: Pietro
authors.initials: P
authors.lastname: Imbrogno
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Andò
authors.forename: Saveria
authors.initials: S
authors.lastname: Aquila
mesh_terms: D000176:Acrosin / Q000378:metabolism; D042964:Acyl-CoA Dehydrogenase / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D002784:Cholesterol / Q000378:metabolism; D004734:Energy Metabolism; D004958:Estradiol / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006801:Humans; D007248:Infertility, Male / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D007328:Insulin / Q000378:metabolism; D007558:Italy; D008049:Lipase / Q000378:metabolism; D008297:Male; D046529:Microscopy, Electron, Transmission; D010766:Phosphorylation; D013075:Sperm Capacitation; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism* / Q000648:ultrastructure; D014280:Triglycerides / Q000378:metabolism; D014646:Varicocele / Q000150:complications* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
chemical_list: C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D007328:Insulin; D014280:Triglycerides; D004958:Estradiol; D002784:Cholesterol; D005954:Glucosephosphate Dehydrogenase; D042964:Acyl-CoA Dehydrogenase; D008049:Lipase; D000176:Acrosin; D005947:Glucose