Mechanism of action of bolandiol (19-nortestosterone-3beta,17beta-diol), a unique anabolic steroid with androgenic, estrogenic, and progestational activities

Activational action of testosterone on androgen receptors protects males preventing temporomandibular joint pain

BACKGROUND

Testosterone protects male rats from Temporomandibular Joint (TMJ) pain. This study investigated whether this protective effect is mediated by an organizational action of testosterone during nervous system development, by central estrogen and androgen receptors and by the 5α-reduced metabolite of testosterone, dihydrotestosterone.

METHODS

A pharmacological approach was used to assess the ability of the androgen receptor antagonist flutamide, the estrogen receptor antagonist ICI 182 780 and the 5-α reductase inhibitor dutasteride to block the protective effect of testosterone, evaluated through the behavioral response induced by a TMJ injection of 0.5% formalin. Flutamide and ICI 182 780 were injected into the medullary subarachnoid space, and dutasteride and testosterone were systemically administered.

RESULTS

The TMJ injection of 0.5% formalin induced a significant nociceptive behavioral response in gonadectomized male and naïve female, but not in sham gonadectomized male rats, confirming that endogenous testosterone prevents TMJ nociception in males. Testosterone administration prevented formalin-induced TMJ nociception in males gonadectomized either in the neonatal (at the day of birth) or adult period and in naïve female rats, suggesting that the protective effect of testosterone on TMJ nociception does not depend on its organizational actions during critical periods of development. The administration of flutamide and dutasteride but not of ICI 182 780 blocked the protective effect of testosterone.

CONCLUSIONS

We conclude that the protective effect of testosterone on TMJ nociception depends on activational actions of dihydrotestosterone on androgen receptors rather than on organizational androgenic actions during central nervous system development or estrogenic actions.

Modulatory effect of gonadotropins on rats' ovaries after nandrolone decanoate administration: a stereological study

BACKGROUND

Nandrolone decanoate (ND) is an anabolic androgenic steroid (AAS) which influences the ovarian structure and function. We assessed the effects of ND on the ovarian volume, number of primordial follicles, and level of hormones and also evaluated the modulatory effects of gonadotropins on the histopathological changes imposed by the administration of ND.

METHODS

Six groups of Sprague-Dawley adult female rats (n=30) were used. The experimental rats were injected intraperitoneally with 3 and 10 mg/kg ND with or without human menopausal gonadotropin (hMG), 10 IU weekly for one month. The vehicle and control rats were administered olive oil and saline, respectively, for the same period of time. The ovarian volume and number of primordial follicles were estimated by stereological methods.

RESULTS

The results showed a decrease in the ovarian volume, number of primordial follicles, and level of gonadotropins in the ND-treated animals compared with the vehicle groups. In the rats treated with 3 mg/kg of ND with hMG, an increase in the ovarian volume and number of primordial follicles was shown as compared to the rats treated with the same dose of ND without hMG.

CONCLUSION

ND exerted detrimental effects on the dimensions of the ovary, number of follicles, and level of sex hormones. However, hMG, prevented the harmful effects of ND (at least in a low dose) on the ovarian follicles.

In vitro androgen bioassays as a detection method for designer androgens

Androgens are the class of sex steroids responsible for male sexual characteristics, including increased muscle mass and decreased fat mass. Illicit use of androgen doping can be an attractive option for those looking to enhance sporting performance and/or physical appearance. The use of in vitro bioassays to detect androgens, especially designer or proandrogens, is becoming increasingly important in combating androgen doping associated with nutritional supplements. The nutritional sports supplement market has grown rapidly throughout the past decade. Many of these supplements contain androgens, designer androgens or proandrogens. Many designer or proandrogens cannot be detected by the standard highly-sensitive screening methods such as gas chromatography-mass spectrometry because their chemical structure is unknown. However, in vitro androgen bioassays can detect designer and proandrogens as these assays are not reliant on knowing the chemical structure but instead are based on androgen receptor activation. For these reasons, it may be advantageous to use routine androgen bioassay screening of nutraceutical samples to help curb the increasing problem of androgen doping.

Enhanced evaluation of selective androgen receptor modulators in vivo

Selective androgen receptor modulators (SARMs) are a class of drugs that control the activity of the androgen receptor (AR), which mediates the response to androgens, in a tissue-selective fashion. They are specifically designed to reduce the possible complications that result from the systemic inhibition or activation of AR in patients with diseases that involve androgen signalling. However, there are no ideal in vivo models for evaluating candidate SARMs. Therefore, we created a panel of androgen-responsive genes in clinically relevant AR expressing tissues including prostate, skin, bone, fat, muscle, brain and kidney. We used select genes from this panel to compare transcriptional changes in response to the full agonist dihydrotestosterone (DHT) and the SARM bolandiol at 16 h and 6 weeks. We identified several genes in each tissue whose expression at each of these time points correlates with the known tissue-specific effects of these compounds. For example, in the prostate we found four genes whose expression was much lower in animals treated with bolandiol compared with animals treated with DHT for 6 weeks, which correlated well with differences in prostate weight. We demonstrate that adding molecular measurements (androgen-regulated gene expression) to the traditional physiological measurements (tissue weights, etc.) makes the evaluation of potential SARMs more accurate, thorough and perhaps more rapid by allowing measurement of selectivity after only 16 h of drug treatment.

Anabolic androgenic steroid abuse: multiple mechanisms of regulation of GABAergic synapses in neuroendocrine control regions of the rodent forebrain

Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone originally developed for clinical purposes but are now predominantly taken at suprapharmacological levels as drugs of abuse. To date, almost 100 different AAS compounds that vary in metabolic fate and physiological effects have been designed and synthesised. Although they are administered for their ability to enhance muscle mass and performance, untoward side effects of AAS use include changes in reproductive and sexual behaviours. Specifically, AAS, depending on the type of compound administered, can delay or advance pubertal onset, lead to irregular oestrous cyclicity, diminish male and female sexual behaviours, and accelerate reproductive senescence. Numerous brains regions and neurotransmitter signalling systems are involved in the generation of these behaviours, and are potential targets for both chronic and acute actions of the AAS. However, critical to all of these behaviours is neurotransmission mediated by GABA(A) receptors within a nexus of interconnected forebrain regions that includes the medial preoptic area, the anteroventral periventricular nucleus and the arcuate nucleus of the hypothalamus. We review how exposure to AAS alters GABAergic transmission and neural activity within these forebrain regions, taking advantage of in vitro systems and both wild-type and genetically altered mouse strains, aiming to better understand how these synthetic steroids affect the neural systems that underlie the regulation of reproduction and the expression of sexual behaviours.

The Buzz about anabolic androgenic steroids: electrophysiological effects in excitable tissues

Anabolic androgenic steroids (AAS) comprise a large and growing class of synthetic androgens used clinically to promote tissue-building in individuals suffering from genetic disorders, injuries, and diseases. Despite these beneficial therapeutic applications, the predominant use of AAS is illicit: these steroids are self-administered to promote athletic performance and body image. Hand in hand with the desired anabolic actions of the AAS are untoward effects on the brain and behavior. While the signaling routes by which the AAS impose both beneficial and harmful actions may be quite diverse, key endpoints are likely to include ligand-gated and voltage-dependent ion channels that govern the activity of electrically excitable tissues. Here, we review the known effects of AAS on molecular targets that play critical roles in controlling electrical activity, with a specific focus on the effects of AAS on neurotransmission mediated by GABA(A) receptors in the central nervous system.

Strategies and methods to study sex differences in cardiovascular structure and function: a guide for basic scientists

Background

Cardiovascular disease remains the primary cause of death worldwide. In the US, deaths due to cardiovascular disease for women exceed those of men. While cultural and psychosocial factors such as education, economic status, marital status and access to healthcare contribute to sex differences in adverse outcomes, physiological and molecular bases of differences between women and men that contribute to development of cardiovascular disease and response to therapy remain underexplored.

Methods

This article describes concepts, methods and procedures to assist in the design of animal and tissue/cell based studies of sex differences in cardiovascular structure, function and models of disease.

Results

To address knowledge gaps, study designs must incorporate appropriate experimental material including species/strain characteristics, sex and hormonal status. Determining whether a sex difference exists in a trait must take into account the reproductive status and history of the animal including those used for tissue (cell) harvest, such as the presence of gonadal steroids at the time of testing, during development or number of pregnancies. When selecting the type of experimental animal, additional consideration should be given to diet requirements (soy or plant based influencing consumption of phytoestrogen), lifespan, frequency of estrous cycle in females, and ability to investigate developmental or environmental components of disease modulation. Stress imposed by disruption of sleep/wake cycles, patterns of social interaction (or degree of social isolation), or handling may influence adrenal hormones that interact with pathways activated by the sex steroid hormones. Care must be given to selection of hormonal treatment and route of administration.

Conclusions

Accounting for sex in the design and interpretation of studies including pharmacological effects of drugs is essential to increase the foundation of basic knowledge upon which to build translational approaches to prevent, diagnose and treat cardiovascular diseases in humans.