Steroidogenic Acute Regulatory Protein in Eels: cDNA Cloning and Effects of ACTH and Seawater Transfer on Its mRNA Expression

The rate limiting step in steroidogenesis is cholesterol transport through the outer to the inner mitochondrial membrane and the cytochrome P450 side chain cleavage (P450scc) complex. The protein factor responsible for this transport, and as such necessary for regulating the acute production of steroids, has been identified and named the steroidogenic acute regulatory protein (StAR). We investigated the expression of StAR in functional and non-functional adrenal neoplasms and compared the expression with that of P450scc. Poly A RNA was extracted from normal adrenal glands (NAG, n=5), aldosterone producing adenomas (APA, n=4), cortisol producing adenomas (CPA, n=5), adrenocortical carcinomas (ACC, n=6) and non-functional adenomas (NFA, n=3), electrophoresed through a 1% agarose gel, blotted and hybridised with a PCR-generated cDNA labelled with [(32)P]CTP. The blots were stripped and re-hybridised with a P450scc cDNA and a mouse beta-actin probe. Compared with P450scc, StAR mRNA expression showed little variability in the magnitude of expression and did not correlate with the endocrine profiles (NAG: StAR 100+/-16%, P450scc 100+/-14%; APA: StAR 80+/-3%, P450scc 94+/-13%; CPA: StAR 71+/-10%, P450scc 109+/-15%; NFA: StAR 64+/-9.5%, P450scc 18+/-5%; means+/-s.e.m.). ACC expressed low levels of both genes probably as a result of dedifferentiation (StAR 29+/-9%, P450scc 46+/-18%). Incubation of the NCI-h295 tumour cell line with 10nmol ACTH and 10micromol forskolin induced an increase in the abundance of StAR and P450scc mRNA, demonstrating gene regulation by the cAMP protein kinase A pathway. Furthermore, we incubated the NCI-h295 tumour cell line with the adrenostatic compounds, aminoglutethimide and metyrapone. We could not detect an effect on the expression of StAR mRNA, whereas the expression of P450scc mRNA was significantly reduced. We conclude that, in contrast to P450scc, StAR seems to be evenly expressed in adrenocortical adenomas. Therefore, the endocrine activity of a given tumour cannot be explained by the abundance of StAR expression. In ACC, both StAR and P450scc expression is low, explaining the relatively inefficient steroid production of these tumours.

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Oxygen Concentration Is an Important Factor for Modulating Progesterone Synthesis in Bovine Corpus Luteum

Endocrinology ◽

10.1210/en.2005-1611 ◽

2006 ◽

Vol 147 (9) ◽

pp. 4273-4280 ◽

Cited By ~ 37

Author(s):

Ryo Nishimura ◽

Ryosuke Sakumoto ◽

Yuko Tatsukawa ◽

Tomas J. Acosta ◽

Kiyoshi Okuda

Keyword(s):

Mrna Expression ◽

Corpus Luteum ◽

Oxygen Deficiency ◽

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Low Oxygen ◽

Luteal Cells ◽

O2 Concentration ◽

Oxygen Condition ◽

Steroidogenic Acute Regulatory

Oxygen deficiency caused by a decrease in the blood supply is known to induce various responses of cells. Because luteal blood flow has been shown to decrease during luteolysis, a low-oxygen condition seems to be an integral part of the environment during luteolysis. To determine whether a low-oxygen condition is associated with functional luteolysis, we examined the influence of reduced oxygen tension on the luteal progesterone (P4) generating system in cultured bovine midluteal cells. Luteal cells obtained from midcycle corpus luteum (d 8–12) were incubated under different O2 concentrations (20, 10, 5, 3% O2) with or without LH for 24 h. P4 production decreased with decreasing O2 concentration but was significantly stimulated by LH regardless of O2 concentration. After 8 h of culture, both basal and LH-stimulated P4 production was significantly lower under 3% O2 than under 20% O2. Low-oxygen condition also inhibited pregnenolone production. Cytochrome P450 side-chain cleavage enzyme (P450scc) mRNA expression, measured by quantitative PCR, decreased under low-oxygen condition in both non-LH-treated and LH-treated cells. Low-oxygen condition did not affect the expressions of steroidogenic acute regulatory protein mRNA or protein, whereas steroidogenic acute regulatory protein mRNA expression was stimulated by LH during 4 h of culture. Low-oxygen condition also did not affect 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase mRNA expression or the activity of the enzyme in the cells, regardless of the incubation period. The overall results indicate that a low-oxygen condition decreases P4 synthesis by attenuating P450scc production and P450scc activity in bovine luteal cells and suggest that oxygen deficiency is an essential condition for the progression of luteolysis in cattle.

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Changes of steroidogenic acute regulatory protein mRNA expression in postnatal rat development

Developmental Brain Research ◽

10.1016/s0165-3806(02)00576-x ◽

2002 ◽

Vol 139 (2) ◽

pp. 247-254 ◽

Cited By ~ 18

Author(s):

Hyun Joon Kim ◽

Chang Hwan Park ◽

Gu Seob Roh ◽

Sang Soo Kang ◽

Gyeong Jae Cho ◽

...

Keyword(s):

Mrna Expression ◽

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Rat Development ◽

Steroidogenic Acute Regulatory

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Effects of the β2-agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats

Journal of Veterinary Pharmacology and Therapeutics ◽

10.1111/j.1365-2885.2010.01176.x ◽

2010 ◽

Vol 33 (6) ◽

pp. 558-563 ◽

Cited By ~ 1

Author(s):

J.-K. MA ◽

W.-J. ZHU

Keyword(s):

Mrna Expression ◽

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Adult Rats ◽

Steroidogenic Acute Regulatory ◽

Β2 Agonist

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Interleukin-1 inhibits Leydig cell steroidogenesis without affecting steroidogenic acute regulatory protein messenger ribonucleic acid or protein levels

Journal of Endocrinology ◽

10.1677/joe.0.1560461 ◽

1998 ◽

Vol 156 (3) ◽

pp. 461-467 ◽

Cited By ~ 28

Author(s):

T Lin ◽

D Wang ◽

DM Stocco

Keyword(s):

Mrna Expression ◽

Leydig Cell ◽

Leydig Cells ◽

Interleukin 1 ◽

Mrna Level ◽

Primary Cultures ◽

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Protein Levels ◽

Steroidogenic Acute Regulatory

The rate-limiting step of steroidogenesis is the transport of the substrate cholesterol from the outer to the inner mitochondrial membrane which involves a cycloheximide-sensitive newly synthesized protein. A protein believed to carry out this function was recently cloned from MA-10 mouse Leydig tumor cells and named the steroidogenic acute regulatory protein (StAR). In the present study, we evaluated the expression and regulation of StAR in primary cultures of rat Leydig cells. StAR mRNA was expressed in Leydig cells as two major transcripts of 3.8 and 1.7 kb and one minor transcript of 1.2 kb. Induction of StAR mRNA transcripts could be detected as early as 30 min after the addition of human choriogonadotropin (hCG) with peak levels attained between 2 and 4 h. hCG in concentrations of 0.1-10 ng/ml caused a dose-dependent increase in StAR mRNA expression. hCG administered at a dose of 10 ng/ml increased the 3.8 kb StAR mRNA level about 14-fold and the 1.7 kb StAR mRNA level about 13.6-fold. hCG-stimulated StAR mRNA was associated with increased StAR protein levels as determined by immunoblot analysis (a 4.5-fold increase). Murine interleukin-1 alpha (mIL-1 alpha) at a concentration of 100 ng/ml inhibited hCG-induced cytochrome P450 side-chain cleavage (P450 scc) mRNA expression and testosterone formation almost completely. Interestingly, mIL-1 alpha had no effect on hCG-induced StAR mRNA or protein levels. Furthermore, mIL-1 alpha (10 ng/ml) decreased conversion of (22R)-hydroxycholesterol to testosterone while the conversion of pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone and androstenedione to testosterone were not affected. These results indicate that the major inhibitory effect of IL-1 on Leydig cell function occurs at the level of P450 scc.

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Bisphenol A stimulates steroidogenic acute regulatory protein mRNA expression and progesterone production in rat immature granulosa cells

Toxicology Letters ◽

10.1016/j.toxlet.2015.08.911 ◽

2015 ◽

Vol 238 (2) ◽

pp. S320

Author(s):

D. Samardzija ◽

K. Pogrmic-Majkic ◽

S. Fa ◽

S. Gasic ◽

N. Andric

Keyword(s):

Bisphenol A ◽

Mrna Expression ◽

Granulosa Cells ◽

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Progesterone Production ◽

Steroidogenic Acute Regulatory

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Von Hermaphroditos der griechischen Mythologie bis zu DSD der Moderne

Praxis ◽

10.1024/1661-8157.98.1.31 ◽

2008 ◽

Vol 98 (1) ◽

pp. 31-34

Author(s):

Oestmann ◽

Mullis ◽

Stanga

Keyword(s):

Regulatory Protein ◽

Steroidogenic Acute Regulatory Protein ◽

Sich Eine ◽

Fand Sich ◽

Steroidogenic Acute Regulatory

Wir berichten über eine heute 34-jährige Frau, die im Alter von 6 Monaten wegen rezidivierendem Erbrechen hospitalisiert werden musste. Als Ursache fand sich eine Nebenniereninsuffizienz mit Verminderung sämtlicher Hormone der Steroidhormonbiosynthese. Die weiteren Abklärungen ergaben bei dem phänotypisch weiblichen Säugling eine lipoide kongenitale adrenale Hyperplasie mit 46,XY DSD. 24 Jahre später konnte in der DNS-Sequenzanalyse ein homozygoter, in der Schweiz vorkommender Basenaustausch des steroidogenic acute regulatory protein-Gens gefunden werden, welcher zu einem Aminosäurenaustausch Leucin 260 Prolin (L260P) führt.

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