Induced synthesis of P450 Aromatase and 17β-estradiol by D-aspartate in frog brain

Abstract

SUMMARY D-Aspartic acid is an endogenous amino acid occurring in the endocrine glands as well as in the nervous system of various animal phyla. Our previous studies have provided evidence that D-aspartate plays a role in the induction of estradiol synthesis in gonads. Recently, we have also demonstrated that D-aspartic acid induces P450 aromatase mRNA expression in the frog (Pelophylax esculentus) testis. P450 aromatase is the key enzyme in the estrogen synthetic pathway and irreversibly converts testosterone into 17-estradiol. In this study, we firstly investigated the immunolocalisation of P450 aromatase in the brain of P. esculentus, which has never previously been described in amphibians. Therefore, to test the hypothesis that D-aspartate mediates a local synthesis of P450 aromatase in the frog brain, we administered D-aspartate in vivo to male frogs and then assessed brain aromatase expression, sex hormone levels and sex hormone receptor expression. We found that D-aspartate enhances brain aromatase expression (mRNA and protein) through the CREB pathway. Then, P450 aromatase induces 17-estradiol production from testosterone, with a consequent increase of its receptor. Therefore, the regulation of D-aspartate-mediated P450 aromatase expression could be an important step in the control of neuroendocrine regulation of the reproductive axis. Accordingly, we found that the sites of P450 aromatase immunoreactivity in the frog brain correspond to the areas known to be involved in neurosteroid synthesis.

The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review

“…D-Asp inhances aromatase activity, with consequent production of estradiol from testosterone (6, 42, 43). …”

Cyp19a1 (Aromatase) Expression in the Xenopus Brain at Different Developmental Stages

“…In amphibians, two studies have reported distributions for immunoreactive aromatase; data were reported on the distribution of the aromatase protein in the preoptic and mesencephalic tegmentum of adult male Penaeus esculentus and in the choroid plexus, olfactory bulbs and paleocortex of X. laevis at larva (NF50) stage . As noted in the Introduction, there have been a number of technical complications regarding the use of aromatase antisera in mammals, although there has been greater reliability in some non‐mammalian vertebrates.…”

Estrogens synthesized and acting within a spinal oligomer suppress spinal endomorphin 2 antinociception: ebb and flow over the rat reproductive cycle

“…The following antibodies were used for (1) IP: anti-mGluR 1 (sc-47131; 2 µg per 800 µg of total protein), anti-ERα (sc-71064; 3 µg per 800 µg of total protein), anti-aromatase (sc-14245; 3 µg per 800 µg of total protein), all purchased from Santa Cruz Biotechnology (SCB); (2) Western blot: anti-mGluR 1 (US Biologicals, M3884-75C; 1:1000), anti-ERα (SCB, sc-542; 1:250), anti-aromatase (abcam, ab124776; 1:40,000), anti-GPR30 (SCB, sc-48524-R; 1:250), anti-MOR (raised in rabbit against carboxyl-terminal 50 aa of MOR; generous gift from Dr. Thomas Cote; 1:1000) [18], anti-pSERα (SCB, sc-12915-R; 1:250); and (3) ICC: anti-ERα (SCB, sc-542; 1:1000) [62], anti-MOR 1 (raised in guinea pig against aa 384–398 of MOR 1 ; 1:1000) [5], anti-mGluR 1 (BD Biosciences, 610964; 1:1000), anti-aromatase (abcam, ab69653; 1:1000) [13], and anti-EM2 (generated by the Wessendorf laboratory against the full sequence of EM2 and affinity isolated; 1:1000) [79; 80]. …”