Effect of chronic ACTH treatment on guinea-pig adrenal steroidogenesis: Steroid plasma levels, steroid adrenal levels, activity of steroidogenic enzymes and their steady-state mRNA levels

1992 ◽  
Vol 41 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Patricia H. Provencher ◽  
Yves Tremblay ◽  
Simon Caron ◽  
Alain Belanger
Keyword(s):  
Steady State ◽  
Guinea Pig ◽  
Plasma Levels ◽  
Mrna Levels ◽  
Steroidogenic Enzymes ◽  
Adrenal Steroidogenesis ◽  
Acth Treatment

Effects of C19 steroids on adrenal steroidogenic enzyme activities and their mRNA levels in guinea-pig fasciculata-glomerulosa cells in primary culture

1992 ◽  
Vol 132 (2) ◽  
pp. 269-276 ◽  
Author(s):  
P. H. Provencher ◽  
Y. Tremblay ◽  
A. Bélanger
Keyword(s):  
Guinea Pig ◽  
Primary Culture ◽  
Oxygen Tension ◽  
Enzyme Activities ◽  
Inhibitory Effect ◽  
Mrna Levels ◽  
Hydroxylase Activity ◽  
Steroidogenic Enzymes ◽  
Steroidogenic Enzyme ◽  
Steroid Synthesis

ABSTRACT The present study examined the effects of steroids on steroidogenic enzyme activity in adrenal glands. Guinea-pig fasciculata-glomerulosa (FG) cells maintained in primary culture were exposed to steroids for 48 h. Although the treatment with androstenedione alone had no effect on 3β-hydroxysteroid dehydrogenase 4-ene-5-ene-isomerase (3β-HSD), 17-hydroxylase and 17,20-lyase activities, there was inhibition of 11-hydroxylase and 21-hydroxylase activities. When FG cells were exposed to 10 nmol ACTH/l for the last 24 h of incubation, ACTH alone had no effect on steroidogenic enzymes but, while combined with androstenedione, it further decreased 21-hydroxylase activity and stimulated 17-hydroxylase and 17,20-lyase activities. Cortisol, corticosterone, oestradiol and 11β-hydroxy androstenedione had no effect on steroidogenic enzyme activities while the inhibitory effect on 21-hydroxylase activity was only observed with androstenedione, testosterone and dihydrotestosterone. Addition of hydroxyflutamide, a pure antiandrogen, did not block the inhibitory effect of androstenedione on 21-hydroxylase and 11-hydroxylase activities. The reduction in oxygen tension from 19 to 2% which was aimed at examining the oxygen-mediated effects on steroidogenic enzymes, revealed that the reduction in 21-hydroxylase activity induced by androstenedione could not be prevented by low oxygen tension. An interaction of C19 steroids at the level of the enzymes is also suggested by our finding that androstenedione had no effect on basal and ACTH-stimulated steady-state 11-hydroxylase, 17-hydroxylase, 17,20-lyase and 21-hydroxylase mRNA levels. These results indicate that C19 steroids alter the adrenal steroidogenic enzyme activities in such a manner that C19 steroid synthesis is increased while glucocorticoid production is inhibited. The mechanism of action of C19 steroids does not involve gene expression for steroidogenic enzymes but probably a direct interaction with steroidogenic enzymes, namely 21-hydroxylase, 17-hydroxylase and 17,20-lyase. Our data suggest that C19 steroids may reduce the amount of 21-hydroxylase in the microsomal fraction which may have a major impact on the levels of microsomal P450 reductase available for 17-hydroxylase and 17,20-lyase activities. Journal of Endocrinology (1992) 132, 269–276

Hypocretin/orexin increases the expression of steroidogenic enzymes in human adrenocortical NCI H295R cells

2009 ◽  
Vol 297 (5) ◽  
pp. R1601-R1609 ◽  
Author(s):  
Jan Wenzel ◽  
Nicole Grabinski ◽  
Cordula A. Knopp ◽  
Andreas Dendorfer ◽  
Manjunath Ramanjaneya ◽  
...  
Keyword(s):  
Adrenal Glands ◽  
Synthesis Rate ◽  
Receptor Subtypes ◽  
Mrna Levels ◽  
Steroidogenic Enzymes ◽  
Orexin A ◽  
Orexin Receptors ◽  
Adrenal Steroidogenesis ◽  
Intracellular Ca ◽  
H295r Cells

Hypocretins/orexins act through two receptor subtypes: OX1 and OX2. Outside the brain, orexin receptors are expressed in adrenal glands, where orexins stimulate the release of glucocorticoids. To further address the regulation of steroidogenesis, we analyzed the effect of orexins on the expression of steroidogenic enzymes in human adrenocortical National Cancer Institute (NCI) H295R cells by qPCR. In NCI H295R cells, OX2 receptors were highly expressed, as they were in human adrenal glands. After treatment of NCI H295R cells with orexin A for 12–24 h, the cortisol synthesis rate was significantly increased, whereas 30 min of treatment showed no effect. While CYP11B1 and CYP11B2 mRNA levels were increased already at earlier time points, the expression of HSD3B2 and CYP21 mRNA was significantly up-regulated after treatment with orexin A for 12 h. Likewise, orexin B increased CYP21 and HSD3B2 mRNA levels showing, however, a lower potency compared with orexin A. The mRNA levels of CYP11A and CYP17 were unaffected by orexin A. OX2 receptor mRNA levels were down-regulated after 12 and 24 h of orexin A treatment. Orexin A increased intracellular Ca2+ but not cAMP concentrations in NCI H295R cells. Furthermore, inhibition of PKC and MAPK kinase/ERK kinase (MEK1/2) prevented the increase of HSD3B2 expression by orexin A. Accordingly, orexin A treatment of NCI H295R cells markedly enhanced ERK1/2 phosphorylation that was prevented by PKC and, in part, PKA inhibition. In conclusion, orexins may influence adrenal steroidogenesis by differential regulation of the expression of steroidogenic enzymes involving Ca2+, as well as PKC-ERK1/2 signaling.

scholarly journals Effects of sex steroids on gonadotropin (FSH and LH) regulation in coho salmon (Oncorhynchus kisutch)

1998 ◽  
Vol 21 (3) ◽  
pp. 291-306 ◽  
Author(s):  
JT Dickey ◽  
P Swanson
Keyword(s):  
Steady State ◽  
Plasma Levels ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Hormone Treatment ◽  
Beta Subunits ◽  
Mrna Levels ◽  
Rnase Protection ◽  
Single Transcript

The effect of steroid hormone treatment on coho salmon (Oncorhynchus kisutch) was examined. The cDNAs for coho salmon FSH beta and LH beta subunits were cloned and sequenced using reverse transcriptase PCR. Northern blot analysis revealed that a single transcript of 1 kb for each of these subunits was present in the pituitaries of vitellogenic and spermiating coho salmon. RNase protection assays (RPAs) were developed to quantify FSH beta and LH beta subunit transcript levels. For the RPAs, antisense RNA probes and sense RNA standards were prepared from a region of the cDNAs which spanned the signal peptide and a portion of the mature protein. These RPAs were used to examine the effects of exogenous steroids including testosterone, estradiol-17beta (E2) and 17alpha, 20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-P) in vivo, in coho salmon at three time points during the spring period of gonadal growth when plasma levels of FSH are increasing. Both testosterone and E2 increased steady state mRNA levels of LH beta, whereas E2 decreased steady state mRNA levels of FSH beta in one experiment. Thus, the RPAs were able to detect changes in steady state mRNA levels in response to exogenous steroid treatment. Plasma and pituitary levels of FSH and LH were also measured using RIA. Throughout the experimental series, FSH plasma levels decreased in response to exogenous testosterone and E2 administration, while 17alpha,20beta-P had no effect on FSH plasma levels. Plasma LH levels were not detected throughout the course of the experiment. Pituitary LH increased in response to testosterone and E2, while pituitary FSH levels did not change. 17alpha,20beta-P had no effect on pituitary FSH or LH content during the experiment. Thus, regulation of the gonadotropins in coho salmon occurs at both the transcriptional as well as the translational level. Testosterone and E2 appear to have negative feedback effects on FSH, but positive feedback on LH.

Studies of adrenal steroidogenic enzymes in guinea pigs

1992 ◽  
Vol 262 (6) ◽  
pp. E869-E874
Author(s):  
P. H. Provencher ◽  
Y. Tremblay ◽  
B. Belanger ◽  
A. Belanger
Keyword(s):  
Steady State ◽  
Adrenocorticotropic Hormone ◽  
Northern Blot Analysis ◽  
Side Chain ◽  
Zona Fasciculata ◽  
Mrna Levels ◽  
Steroidogenic Enzymes ◽  
Zona Reticularis ◽  
Chain Cleavage ◽  
Steady State Levels

In the present study we found that 3 beta-hydroxysteroid dehydrogenase 4-ene-5-ene-isomerase (3 beta-HSD), 17-hydroxylase and 17,20-lyase (P-450c17), and 21-hydroxylase (P-450c21) activities in a suspension of cells from guinea pig zona reticularis (RE) were 10- to 15-fold less than those measured in cells from zona fasciculata-glomerulosa (FG). Whereas the secretion of cortisol and C-19 steroids was remarkably increased during treatment of FG cells with adrenocorticotropic hormone (ACTH), no response could be detected when using cells from zona RE. By contrast, the measurement of a series of C-21 and C-19 steroids shows that the concentrations of several steroids were greater in the zona RE than in the zona FG. In addition, using Northern blot analysis, we have observed that the basal steady-state levels of mRNA for cholesterol side-chain cleavage (P-450scc), 3 beta-HSD, P-450c21, P-450c17, and P-450c11 were in the same range in the two zones and an administration of ACTH caused, in both zona FG and zona RE, a two- to threefold decrease in P-450c17 and P-450c21 steady-state mRNA levels, whereas P-450c11, 3 beta-HSD, and P-450scc steady-state mRNA levels remained unchanged. Our data suggest the presence of some factor(s) capable of rapidly deactivating the steroidogenic enzymes in the zona RE.

Effects of RU 486 on adrenal steroidogenesis in the guinea-pig

1991 ◽  
Vol 130 (1) ◽  
pp. 71-78 ◽  
Author(s):  
P. H. Provencher ◽  
A Bélanger ◽  
J. Fiet
Keyword(s):  
Guinea Pig ◽  
Concomitant Treatment ◽  
Cortisol Secretion ◽  
Direct Effects ◽  
Steroidogenic Enzymes ◽  
Steroid Secretion ◽  
Ru 486 ◽  
Adrenal Steroidogenesis ◽  
17 Hydroxyprogesterone ◽  
Synthetic Glucocorticoid

ABSTRACT Recent reports have shown that RU 486, a synthetic glucocorticoid and progestin antagonist, has direct effects on tissues secreting steroids. In order to characterize the effects of RU 486 on steroidogenesis further, guinea-pig fasciculata-glomerulosa (FG) cells in primary culture were treated for 48 h with RU 486. RU 486 caused an alteration of basal as well as ACTH-stimulated steroid secretion. Corticosterone and cortisol secretion decreased by 50% while the secretion of 17-hydroxyprogesterone and C19 steroids were increased. The activity of steroidogenic enzymes was measured using tritiated steroids. In RU 486-treated cells, the activity of 21-hydroxylase was dramatically inhibited while there was an increase in 17-hydroxylase and 17,20-desmolase activities. The effects of RU 486 on enzyme activities were dependent upon dose and time. The effects of the compound were not reversed by concomitant treatment of FG cells with R-5020 or dexamethasone, thus suggesting that RU 486 acted directly on steroidogenic enzymes to alter their activity. Journal of Endocrinology (1991) 130, 71–78

Plasma levels of progesterone and oestrogen in the pregnant guinea-pig

Reproduction ◽  
1971 ◽  
Vol 25 (2) ◽  
pp. 305-306 ◽  
Author(s):  
D. Illingworth ◽  
Challis ◽  
A Henville
Keyword(s):  
Guinea Pig ◽  
Plasma Levels

Tanshinone IIA Promotes Macrophage Cholesterol Efflux and Attenuates Atherosclerosis of apoE-/- Mice by Omentin-1/ABCA1 Pathway

2019 ◽  
Vol 20 (5) ◽  
pp. 422-432 ◽  
Author(s):  
Yu-lin Tan ◽  
Han-xiao Ou ◽  
Min Zhang ◽  
Duo Gong ◽  
Zhen-wang Zhao ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Lipid Content ◽  
Plasma Levels ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
Tanshinone Iia ◽  
Lipoprotein Cholesterol ◽  
Mrna Levels ◽  
Cellular Lipid ◽  
Oil Red O

Background: Tanshinone IIA (Tan IIA) and Omentin-1 have a protective role in the cardiovascular system. However, if and how Tan IIA and Omentin-1 regulate cholesterol metabolism in macrophages has not been fully elucidated. Objective: To investigate the possible mechanisms of Tan IIA and Omentin-1 on preventing macrophage cholesterol accumulation and atherosclerosis development. Methods: The effect of Tan IIA on the protein and mRNA levels of Omentin-1 and ATP-binding cassette transporter A1 (ABCA1) in macrophages was examined by Western blot and qRT-PCR assay, respectively. Cholesterol efflux was assessed by liquid scintillation counting (LSC). Cellular lipid droplet was measured by Oil Red O staining, and intracellular lipid content was detected by high performance liquid chromatography (HPLC). In addition, the serum lipid profile of apoE−/− mice was measured by enzymatic method. The size of atherosclerotic lesion areas and content of lipids and collagen in the aortic of apoE−/− mice were examined by Sudan IV, Oil-red O, and Masson staining, respectively. Results: Tan IIA up-regulated expression of Omentin-1 and ABCA1 in THP-1 macrophages, promoting ABCA1-mediated cholesterol efflux and consequently decreasing cellular lipid content. Consistently, Tan IIA increased reverse cholesterol transport in apoE−/− mice. Plasma levels of high-density lipoprotein cholesterol (HDL-C), ABCA1 expression and atherosclerotic plaque collagen content were increased while plasma levels of low-density lipoprotein cholesterol (LDL-C) and atherosclerotic plaque sizes were reduced in Tan IIA-treated apoE−/− mice. These beneficial effects were, however, essentially blocked by knockdown of Omentin-1. Conclusion: Our results revealed that Tan IIA promotes cholesterol efflux and ameliorates lipid accumulation in macrophages most likely via the Omentin-1/ABCA1 pathway, reducing the development of aortic atherosclerosis.

scholarly journals Genomic structure of murine methylmalonyl-CoA mutase: evidence for genetic and epigenetic mechanisms determining enzyme activity

1993 ◽  
Vol 296 (3) ◽  
pp. 663-670 ◽  
Author(s):  
M F Wilkemeyer ◽  
E R Andrews ◽  
F D Ledley
Keyword(s):  
Enzyme Activity ◽  
Steady State ◽  
Transcription Initiation ◽  
Cultured Cells ◽  
Genomic Structure ◽  
Genetic Regulation ◽  
Regulatory Elements ◽  
Transcription Unit ◽  
Mrna Levels ◽  
Sequence Motifs

Methylmalonyl-CoA mutase (MCM) is a nuclear-encoded mitochondrial matrix enzyme. We have reported characterization of murine MCM and cloning of a murine MCM cDNA and now describe the murine Mut locus, its promoter and evidence for tissue-specific variation in MCM mRNA, enzyme and holo-enzyme levels. The Mut locus spans 30 kb and contains 13 exons constituting a unique transcription unit. A B1 repeat element was found in the 3′ untranslated region (exon 13). The transcription initiation site was identified and upstream sequences were shown to direct expression of a reporter gene in cultured cells. The promoter contains sequence motifs characteristic of: (1) TATA-less housekeeping promoters; (2) enhancer elements purportedly involved in co-ordinating expression of nuclear-encoded mitochondrial proteins; and (3) regulatory elements including CCAAT boxes, cyclic AMP-response elements and potential AP-2-binding sites. Northern blots demonstrate a greater than 10-fold variation in steady-state mRNA levels, which correlate with tissue levels of enzyme activity. However, the ratio of holoenzyme to total enzyme varies among different tissues, and there is no correlation between steady-state mRNA levels and holoenzyme activity. These results suggest that, although there may be regulation of MCM activity at the level of mRNA, the significance of genetic regulation is unclear owning to the presence of epigenetic regulation of holoenzyme formation.

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