caa a22 4500 463185358 CHVBK 20180406164851.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s00726-006-0351-9 doi (NATIONALLICENCE)springer-10.1007/s00726-006-0351-9 Involvement of D-Asp in P450 aromatase activity and estrogen receptors in boar testis [Elektronische Daten] [C. Lamanna, L. Assisi, V. Botte, M. M. Di Fiore] Summary.: Mammalian testis contains D-aspartic acid (D-Asp), which enhances testosterone production. D-Asp, on other hand, also stimulates 17β-estradiol synthesis in the ovary of some lower vertebrates. We studied boar testis in order to determine if D-Asp intervenes in 17β-estradiol synthesis in the testis of those mammals which produce significant amounts of estrogens as well as testosterone. The boar testis contains D-Asp (40 ± 3.6 nmol/g tissue) which, according to immunohistological techniques, is localized mainly in Leydig cells, and, to a lesser extent, in sustentacular (Sertoli), peritubular and some germ cells. The enzyme P450aromatase is present in Leydig cells and few germ cells. In vitro experiments showed that the addition of D-Asp to testicular tissue extracts induced a significant increase of aromatase activity, as evaluated by testosterone conversion into 17β-estradiol. The enzyme's Km was not affected by D-Asp (about 25 nM in both control and D-Asp added tests). On the basis of these results we suggest that, as in the ovary, D-Asp is involved in the local control of aromatase activity of boar testis and, therefore, it intervenes in the 17β-estradiol production. In the testis, the D-Asp targets are presumably the Leydig cells, which having also a nuclear estrogen receptor are, in turn, one of the putative targets of the 17β-estradiol that they produce (autocrine effect). Springer-Verlag, 2006 Keywords: P450arom - D-Asp - Estrogen receptors - 17β-estradiol synthesis - Boar testis nationallicence Lamanna C. Department of Life Sciences, Second University of Naples, Caserta, Italy aut Assisi L. Zoological Section of Department of Biological Sciences, University of Naples, Naples, Italy aut Botte V. Zoological Section of Department of Biological Sciences, University of Naples, Naples, Italy aut Di Fiore M. M. Department of Life Sciences, Second University of Naples, Caserta, Italy aut Amino Acids Springer-Verlag 32/1(2007-01-01), 45-51 0939-4451 32:1<45 2007 32 726 https://doi.org/10.1007/s00726-006-0351-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00726-006-0351-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lamanna C. Department of Life Sciences, Second University of Naples, Caserta, Italy aut NATIONALLICENCE 700 1- Assisi L. Zoological Section of Department of Biological Sciences, University of Naples, Naples, Italy aut NATIONALLICENCE 700 1- Botte V. Zoological Section of Department of Biological Sciences, University of Naples, Naples, Italy aut NATIONALLICENCE 700 1- Di Fiore M. M. Department of Life Sciences, Second University of Naples, Caserta, Italy aut NATIONALLICENCE 773 0- Amino Acids Springer-Verlag 32/1(2007-01-01), 45-51 0939-4451 32:1<45 2007 32 726 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer