Neurotoxic properties of the anabolic androgenic steroids nandrolone and methandrostenolone in primary neuronal cultures

Abstract

Anabolic-androgenic steroid (AAS) abuse is associated with multiple neurobehavioral disturbances. The sites of action and the neurobiological sequels of AAS abuse are unclear at present. We investigated whether two different AASs, nandrolone and methandrostenolone, could affect neuronal survival in culture. The endogenous androgenic steroid testosterone was used for comparison. Both testosterone and nandrolone were neurotoxic at micromolar concentrations, and their effects were prevented by blockade of androgen receptors (ARs) with flutamide. Neuronal toxicity developed only over a 48-hr exposure to the steroids. The cell-impermeable analogues testosterone-BSA and nandrolone-BSA, which preferentially target membrane-associated ARs, were also neurotoxic in a time-dependent and flutamide-sensitive manner. Testosterone-BSA and nandrolone-BSA were more potent than their parent compounds, suggesting that membrane-associated ARs were the relevant sites for the neurotoxic actions of the steroids. Unlike testosterone and nandrolone, toxicity by methandrostenolone and methandrostenolone-BSA was insensitive to flutamide, but it was prevented by the glucocorticoid receptor (GR) antagonist RU-486. Methandrostenolone-BSA was more potent than the parent compound, suggesting that its toxicity relied on the preferential activation of putative membrane-associated GRs. Consistently with the evidence that membrane-associated GRs can mediate rapid effects, a brief challenge with methandrostenolone-BSA was able to promote neuronal toxicity. Activation of putative membrane steroid receptors by nontoxic (nanomolar) concentrations of either nandrolone-BSA or methandrostenolone-BSA became sufficient to increase neuronal susceptibility to the apoptotic stimulus provided by β-amyloid (the main culprit of AD). We speculate that AAS abuse might facilitate the onset or progression of neurodegenerative diseases not usually linked to drug abuse.

Neurophysiological Repercussions of Anabolic Steroid Abuse: A Road into Neurodegenerative Disorders

“…In this context, testosterone per se can induce neuroprotective effect against the toxicity induced by Aβ, an effect observed in mixed cortical neuronal cell cultures [107]. This effect was completely abolished by co-exposure with aromatase, suggesting that aromatization and the local generation of estrogen can underlie the testosteroneinduced neuroprotection.…”

“…Interestingly, when these ASs were conjugated to BSA, which impedes the AS to cross the plasma membrane and to bind to the cytosolic AR, the neurotoxicity was further increased. Even so, co-exposure of flutamide prevented both testosterone-and nandrolone-induced neurotoxicity, suggesting that the membrane-attached AR shares pharmacological similarities with the cytosolic receptor [107]. Furthermore, these evidences suggest that activation of membrane-attached AR can recruit distinct downstream signaling pathways that culminate in enhanced cell death, when compared to the cytosolic AR.…”

“…This effect was completely abolished by co-exposure with aromatase, suggesting that aromatization and the local generation of estrogen can underlie the testosteroneinduced neuroprotection. Interestingly, co-exposure with the AR antagonist flutamide can also attenuate the neuroprotection induced by testosterone against Aβ-induced toxicity, implying that activation of classical AR can attenuate the toxicity induced by Aβ oligomers [107]. In addition, the exposure of neuronal cells to nandrolone, a poorly aromatizable AS, did not affect the neurotoxicity induced by Aβ, whereas it was significantly potentiated by exposure to methandrostenolone [107].…”

“…Interestingly, co-exposure with the AR antagonist flutamide can also attenuate the neuroprotection induced by testosterone against Aβ-induced toxicity, implying that activation of classical AR can attenuate the toxicity induced by Aβ oligomers [107]. In addition, the exposure of neuronal cells to nandrolone, a poorly aromatizable AS, did not affect the neurotoxicity induced by Aβ, whereas it was significantly potentiated by exposure to methandrostenolone [107]. However, nandrolone-BSA (bovine serum albumin) conjugate significantly potentiated the Aβ-induced neurotoxicity, whereas the conjugation of BSA further increased the neurotoxic potentiation induced by methandrostenolone per se.…”

“…In cortical neuronal and astrocytic cultures, 48 hours of exposure to 10 mM of testosterone, nandrolone, or methandrostenolone significantly increased neuronal death [107]. Interestingly, when these ASs were conjugated to BSA, which impedes the AS to cross the plasma membrane and to bind to the cytosolic AR, the neurotoxicity was further increased.…”