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Conference abstract2004Peer reviewed

No effect of dietary supplement of phytoestrogens on oestrogen receptor ERα, in testis and epididymidis of male goat kids

Ekstedt, Elisabeth; Ridderstråle, Yvonne; Holm, Lena; Einarsson, Stig; Selstam, Gunnar; Madej, Andrzej

Abstract

Exposure of xenoestrogens to humans and animals is an increasing concern due to their effects on reproduction. Phytoestrogens are non-steroidal substances in many plants with capacity to bind to oestrogen receptors (ER). Presence of ER in the efferent ductules of the mature male goat indicates the importance of estrogens for male reproduction, which in turn have an effect on carbonic anhydrase (CA) activity (Zhou et al., 2001). The present study was undertaken to investigate whether a low addition of phytoestrogens to a normal diet affects thyroid hormone secretion, the establishment of testosterone production and histochemical localization of CA in testis, efferent ductules and thyroid gland during puberty in male goat kids. Four male goat kids were given a standard diet and 3 were given an addition of 3 - 4 mg phytoestrogens/kg body weight in tablets containing genistein, daidzein, biochanin and formononetin. The treatment commenced at 3 months of age and continued until slaughter at 6 months of age. Plasma testosterone, oestrone sulphate, total and free triiodothyronine (T3) and thyroxin (T4) were measured weekly. Testosterone and cyclic AMP were measured in testicular tissue and CA was localized histochemically in thyroids and reproductive organs. After four weeks of treatment, total T3 concentrations were significantly higher in the phytoestrogen treated animals than in the control ones (2.3  0.3 vs. 1.2  0.2 nmol/l, P < 0.01). Plasma testosterone concentrations at week 7 were significantly (P < 0.05) higher in the phytoestrogen treated animals than the control ones (37.5  6.0 vs. 19.1  5.2 nmol/l). Free T3 concentrations in kids exposed to phytoestrogens were significantly higher than in control animals during week 8 and 9 of the experiment. At the end of the experiment plasma testosterone concentrations were slightly lower in treated goats, testosterone and cyclic AMP levels were lower in testicular tissue. Strong staining for CA activity was present in testicular capillaries, nuclei and apical membranes of the non-ciliated cells of the efferent ductules. The thyroid gland showed strong CA activity in the basolateral membranes of the epithelium. No difference was shown between groups. In conclusion, the exposure of male goat kids to low doses of phytoestrogens has an impact on the hormonal changes during puberty as well as the content of cyclic AMP in the testis, but did not alter CA localization in thyroids or reproductive organs

Published in

Upsala Journal Of Medical Sciences, Supplement
2004, Volume: supplement 56, pages: 34
Title: Upsala Journal of Medical Sciences

Conference

The 22nd Conference of European Comparative Endocrinologists