The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.
Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula / Assisi, Loredana; Botte, V; D'Aniello, A; Di Fiore, Mm. - In: REPRODUCTION. - ISSN 1470-1626. - STAMPA. - 121:5(2001), pp. 803-808.
Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula.
ASSISI, LOREDANA;
2001
Abstract
The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.