Adrenal steroidogenesis in the guinea pig: Effects of androgens

Bélanger, Benoît; Caron, Serge; Boudou, P.; Fiet, Jean; Bélanger, Alain

doi:10.1016/0039-128x(92)90033-6

Cited by 12 publications

(10 citation statements)

References 24 publications

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“…In contrast, a dramatic reduction to a mean level of 0.11 ng/ml at 8 weeks was seen in the castrated empty capsule group, which increased to 0.36 ng/ml at 16 weeks. Extremely low but measurable levels of testosterone were previously observed in castrated male guinea pigs within 2 weeks following castration [34], attributable to low-level steroid production by the adrenal glands [38]. The administration of testosterone in silastic capsules to the intact testosterone group resulted in significant elevations of circulating testosterone at 8 and 16 weeks of treatment, in comparison with the group's own baseline.…”

Section: Longitudinal Mri Characterization Of Testosterone and Nandromentioning

confidence: 84%

In vivo MRI quantification of individual muscle and organ volumes for assessment of anabolic steroid growth effects

Tang

Tong

et al. 2008

Steroids

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This study aimed to develop a quantitative and in vivo magnetic resonance imaging (MRI) approach to investigate the muscle growth effects of anabolic steroids. A protocol of MRI acquisition on a standard clinical 1.5 Tesla scanner and quantitative image analysis was established and employed to measure the individual muscle and organ volumes in the intact and castrated guinea pigs undergoing a 16-week treatment protocol by two well-documented anabolic steroids, testosterone and nandrolone, via implanted silastic capsules. High correlations between the in vivo MRI and postmortem dissection measurements were observed for shoulder muscle complex (R = 0.86), masseter (R=0.79), temporalis (R=0.95), neck muscle complex (R=0.58), prostate gland and seminal vesicles (R=0.98), and testis (R=0.96). Furthermore, the longitudinal MRI measurements yielded adequate sensitivity to detect the restoration of growth to or towards normal in castrated guinea pigs by replacing circulating steroid levels to physiological or slightly higher levels, as expected. These results demonstrated that quantitative MRI using a standard clinical scanner provides accurate and sensitive measurement of individual muscles and organs, and this in vivo MRI protocol in conjunction with the castrated guinea pig model constitutes an effective platform to investigate the longitudinal and cross-sectional growth effects of other potential anabolic steroids. The quantitative MRI protocol developed can also be readily adapted for human studies on most clinical MRI scanner to investigate the anabolic steroid growth effects, or monitor the changes in individual muscle and organ volume and geometry following injury, strength training, neuromuscular disorders, and pharmacological or surgical interventions.

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Section: Longitudinal Mri Characterization Of Testosterone and Nandromentioning

confidence: 84%

In vivo MRI quantification of individual muscle and organ volumes for assessment of anabolic steroid growth effects

Tang

Tong

et al. 2008

Steroids

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show abstract

“…Consistent with this notion is our observation that stimulated cAMP production was not affected by sex or GDX. The expression or activity of a number of steroidogenic enzymes in the adrenal has been reported to be increased in females, compared with males, or stimulated by oestrogens and inhibited by androgens (Belanger et al 1991, Gallant et al 1991, Perry & Stalvey 1992, Issacson et al 1993, ElMigdadi et al 1995, Nowak et al 1995. The observation of increased steroidogenic potential in the female may, however, be somewhat secretagogue-specific, as we have recently shown that AII-induced cortisol production is greater in adrenocortical cultures from intact male sheep, than it is in GDX male or intact female sheep (Canny et al 1998).…”

Section: Discussionmentioning

confidence: 99%

The influence of sex and gonadectomy on the hypothalamo-pituitary-adrenal axis of the sheep

Canny

O'Farrell²,

Clarke³

et al. 1999

Journal of Endocrinology

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There is a sex difference in the hypothalamo-pituitaryadrenal (HPA) axis of many species, although there are sparse data on the sheep. In the present study we have compared the HPA axes of intact and gonadectomised adult male and female sheep at the level of the median eminence, pituitary and adrenal glands using a variety of in vitro approaches. The concentration of arginine vasopressin (AVP) was higher (P<0·01) in the median eminence of male than female sheep, and was also elevated by gonadectomy of either sex (P<0·01). The concentration of corticotrophin-releasing factor (CRF) in the median eminence did not differ between the sexes, but was also elevated in both sexes following gonadectomy (P<0·01). Anterior pituitary pro-opiomelanocortin mRNA concentrations were higher (P<0·05) in intact male sheep than in intact females, with the levels in gonadectomised animals of both sexes being intermediate. In contrast to this finding, basal ACTH secretion from anterior pituitary cells was higher (P<0·05) in cultures derived from female sheep than those from males, but gonadectomy was without effect. There was no effect of sex or gonadectomy on in vitro ACTH secretion in response to AVP, CRF or the combination of AVP and CRF, and in all cases the combination of AVP and CRF generated greater (P<0·0001) ACTH secretion than AVP alone. AVP alone was more effective (P<0·01) than CRF alone as an ACTH secretagogue. The adrenal glands were larger (P<0·05) in female than male sheep, with no effect of gonadectomy. Basal cortisol production was greatest (P<0·05) in cultures of adrenal cells from intact male sheep, though ACTH-and 8BrcAMP-induced cortisol production was greater in the cultures of cells from females (P=0·05); there were no effects of gonadectomy. Cultures of adrenocortical cells from male sheep had greater (P<0·05) basal cAMP production, but ACTH-stimulated cAMP production did not differ between any of the groups of animals. These findings show a range of differences in the HPA axis of male and female sheep. Furthermore, they suggest that the heightened activity of the axis in the female occurs primarily due to differences at the level of the adrenal gland, and that greater adrenal responsiveness of female animals is due to differences in the latter stages of steroidogenesis, rather than an effect on ACTH signal transduction at its receptor.

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“…As expected, castration immediately following baseline led to highly significant decreases of circulating testosterone at weeks 5 and 10 ( p < 0.01). Barely measurable levels of testosterone following castration have been observed previously [28], and are attributed to conversion of natural steroid precursors in the body to testosterone by other tissues, such as the adrenal glands [29]. In contrast, testosterone levels of the intact empty group remained well within the normal range across the entire treatment period.…”

Section: Resultsmentioning

confidence: 56%

In vivo MRI evaluation of anabolic steroid precursor growth effects in a guinea pig model

et al. 2009

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Anabolic steroids are widely used to increase skeletal muscle (SM) mass and improve physical performance. Some dietary supplements also include potent steroid precursors or active steroid analogs such as nandrolone. Our previous study reported the anabolic steroid effects on SM in a castrated guinea pig model with SM measured using a highly quantitative magnetic resonance imaging (MRI) protocol. The aim of the current study was to apply this animal model and in vivo MRI protocol to evaluate the growth effects of four widely used over-the-counter testosterone and nandrolone precursors: 4-androstene-3 17-dione (androstenedione), 4-androstene-3β 17β-diol (4-androsdiol), 19-nor-4-androstene-3β-17β-diol (bolandiol) and 19-nor-4-androstene-3 17-dione (19-norandrostenedione). The results showed that providing precursor to castrated male guinea pigs led to plasma steroid levels sufficient to maintain normal SM growth. The anabolic growth effects of these specific precursors on individual and total muscle volumes, sexual organs, and total adipose tissue over a 10-week treatment period, in comparison with those in the respective positive control testosterone and nandrolone groups, were documented quantitatively by MRI.

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Adrenal steroidogenesis in the guinea pig: Effects of androgens

Cited by 12 publications

References 24 publications

In vivo MRI quantification of individual muscle and organ volumes for assessment of anabolic steroid growth effects

In vivo MRI quantification of individual muscle and organ volumes for assessment of anabolic steroid growth effects

The influence of sex and gonadectomy on the hypothalamo-pituitary-adrenal axis of the sheep

In vivo MRI evaluation of anabolic steroid precursor growth effects in a guinea pig model

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