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In the human body, the adrenal steroids collectively regulate a plethora of fundamental functions, including electrolyte and water balance, blood pressure, stress response, intermediary metabolism, inflammation, and immunity. Therefore, adrenal steroidogenesis is an important biochemistry topic for students to learn in order for them to understand health consequences caused by deficiencies of enzymes in the adrenal steroidogenic pathways. However, popular biochemistry textbooks contain insufficient information and may sometimes give students a misimpression about certain aspects of human adrenal steroidogenesis. This article highlights two neglected issues in teaching human adrenal steroidogenesis in popular biochemistry textbooks. The purpose of this article is to draw attention to these issues. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):469-474, 2017., (© 2017 The International Union of Biochemistry and Molecular Biology.)

Steroidogenesis refers to the de novo synthesis of steroid hormones from cholesterol by a number of sequential enzyme catalysed reactions in the adrenal and the gonads. In addition, circulating steroid hormone precursors are further metabolised in selected peripheral tissues. It has been suggested that the biosynthesis of endogenous steroid hormones can be modulated by progestins, used widely by women in female reproductive medicine. However, as a number of structurally diverse progestins with different pharmacological properties are available, it is possible that these synthetic compounds may vary in their effects on steroidogenesis. This review summarises the evidence indicating that progestins influence the biosynthesis of steroid hormones in the adrenal and gonads, as well as the metabolism of these endogenous hormones in the breast, highlighting the limitations to the current knowledge and directions for future research., (Copyright © 2016. Published by Elsevier B.V.)

C11-oxy C19 and C11-oxy C21 steroids have been identified as novel steroids but their function remains unclear. This study aimed to investigate the pre-receptor regulation of C11-oxy steroids by 11β-hydroxysteroid dehydrogenase (11βHSD) interconversion and potential agonist and antagonist activity associated with the androgen (AR) and progesterone receptors (PRA and PRB). Steroid conversions were investigated in transiently transfected HEK293 cells expressing 11βHSD1 and 11βHSD2, while CV1 cells were utilised for agonist and antagonist assays. The conversion of C11-hydroxy steroids to C11-oxo steroids by 11βHSD2 occurred more readily than the reverse reaction catalysed by 11βHSD1, while the interconversion of C11-oxy C19 steroids was more efficient than C11-oxy C21 steroids. Furthermore, 11-ketodihydrotestosterone (11KDHT), 11-ketotestosterone (11KT) and 11β-hydroxydihydrotestosterone (11OHDHT) were AR agonists, while only progestogens, 11β-hydroxyprogesterone (11βOHP4), 11β-hydroxydihydroprogesterone (11βOHDHP4), 11α-hydroxyprogesterone (11αOHP4), 11α-hydroxydihydroprogesterone (11αOHDHP4), 11-ketoprogesterone (11KP4), 5α-pregnan-17α-diol-3,11,20-trione (11KPdione) and 21-deoxycortisone (21dE) exhibited antagonist activity. C11-hydroxy C21 steroids, 11βOHP4, 11βOHDHP4 and 11αOHP4 exhibited PRA and PRB agonistic activity, while only C11-oxo steroids, 11KP4 and 11-ketoandrostanediol (11K3αdiol) demonstrated PRB agonism. While no steroids antagonised the PRA, 11OHA4, 11β-hydroxytestosterone (11OHT), 11KT and 11KDHT exhibited PRB antagonism. The regulatory role of 11βHSD isozymes impacting receptor activation is clear—C11-oxo androgens exhibit AR agonist activity; only C11-hydroxy progestogens exhibit PRA and PRB agonist activity. Regulation by the downstream metabolites of active C11-oxy steroids at the receptor level is apparent—C11-hydroxy and C11-oxo metabolites antagonize the AR and PRB, progestogens the former, androgens the latter. The findings highlight the intricate interplay between receptors and active as well as "inactive" C11-oxy steroids, suggesting novel regulatory tiers. [ABSTRACT FROM AUTHOR]

The adrenal gland is the most common toxicological target of drugs within the endocrine system, and inhibition of adrenal steroidogenesis can be fatal in humans. However, methods to evaluate the adrenal toxicity are limited. The aim of the present study was to verify the usefulness of simultaneous measurement of blood levels of multiple adrenal steroids, including precursors, as a method to evaluate drug effects on adrenal steroidogenesis in cynomolgus monkeys. With this aim, physiological and drug-induced changes in blood levels of adrenal steroids, including cortisol, aldosterone, androgen, and their precursors were examined. First, for physiological changes, intraday and interday changes in blood steroid levels were examined in male and female cynomolgus monkeys. The animals showed circadian changes in steroid levels that are similar to those in humans, while interday changes were relatively small in males. Next, using males, changes in blood steroid levels induced by ketoconazole and metyrapone were examined, which suppress adrenal steroidogenesis via inhibition of CYP enzymes. Consistent with rats and humans, both ketoconazole and metyrapone increased the deoxycorticosterone and deoxycortisol levels, probably via CYP11B1 inhibition, and the increase was observed earlier and with greater dynamic range than the changes in cortisol level. Changes in other steroid levels reflecting the drug mechanisms were also observed. In conclusion, this study showed that in cynomolgus monkeys, simultaneous measurement of blood levels of adrenal steroids, including precursors, can be a valuable method to sensitively evaluate drug effects on adrenal steroidogenesis and to investigate the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Stress-related illnesses rate among the most prevalent non-fatal diseases globally. With the global trend for consumer bias towards natural medicine, the Sceletium plant has become more prominent in the field of natural products. Although potentially useful effects of Sceletium tortuosum on the central nervous system have been reported, limited data is available on effects of the plant in the peripheral compartment. Aim of the study The current study aimed to elucidate the effect(s) of a Sceletium extract (TRI) rich in mesembrine (1% of plant extract w/w), on adrenal steroid biosynthesis. Materials and methods Steroidogenesis was assessed basally and in response to stimuli (forskolin, angiotensin II, KCl), in human adrenocortical carcinoma cells (H295R). Steroid hormone levels were assessed using UPLC-MS/MS. UPLC-MS analyses of TRI identified major alkaloids Δ7-mesembrenone, mesembrenone and mesembrine. Results Highest dose TRI treatment (1 mg/ml, 34.5 μM mesembrine) increased pregnenolone and decreased 16-hydroxyprogesterone levels (both P <0.00001) in forskolin-stimulated conditions only, suggesting CYP17 enzyme inhibition. This led to significant inhibition of forskolin-associated increases in cortisol levels at the highest dose ( P <0.001) and basal cortisol levels across all doses ( P <0.0001). Independently of forskolin, TRI inhibited androstenedione and testosterone production across all doses (both P <0.00001), suggesting inhibition of 3βHSD and 17βHSD respectively. TRI decreased both the angiotensin II- ( P <0.05) and forskolin-induced ( P <0.0001) increases in aldosterone production. Conclusions Our data suggest potentially beneficial effects of TRI in the context of stress and hypertension. These should be further investigated in a whole organism model, while the effects on the androgenic pathway should also be further elucidated. [ABSTRACT FROM AUTHOR]

Purpose: The effect of pantothenic acid (PaA) supplementation on adrenal secretion of corticosterone and progesterone in female rats was investigated. Methods: An in-vitro primary adrenal cell culture system was used. Pregnant rats were given 0.03% PaA in their drinking water throughout pregnancy and the period of lactation. In the first experiment, after weaning, female rats continued to receive 0.03% PaA treatment until 10 weeks of age. The animals were then decapitated and adrenal cells were cultured in the absence or presence of rat adrenocorticotropic hormone (ACTH) for 4 h. In the second experiment, adrenal cells from lactating rats on day 5 of lactation were cultured in the absence or presence of rat ACTH for 4 h. Results: The effect of ACTH at 10 M on corticosterone and progesterone release was greater for PaA-treated cyclic rats than for control cyclic rats. The effect of ACTH at 10 M on corticosterone release was greater for PaA-treated lactating rats than for control lactating rats. Circulating ACTH and corticosterone levels in PaA-treated and control cyclic and lactating rats were no different. Conclusions: These results indicate that PaA supplementation induced hyperresponsiveness to ACTH stimulation in cyclic and lactating female rats. These results clearly demonstrated that PaA is an essential factor in adrenal steroidogenesis of female rats. [ABSTRACT FROM AUTHOR]