Role of the steroidogenic acute regulatory protein (StAR) in steroidogenesis

Stocco, Douglas M.; Clark, Barbara J.

doi:10.1016/0006-2952(95)02093-4

Cited by 242 publications

(142 citation statements)

References 106 publications

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“…Thus, regulation of P4 production in luteal cells is related more to transport of cholesterol within the cell than to changes in the activity of steroidogenic enzymes (Wiltbank et al, 1993. A number of proteins have been postulated to be involved with transport of cholesterol (sterol carrier protein-2, peripheral benzodiazepine receptor), however the key role of StAR has been the best characterized (Pescador et al, 1996;Stocco and Clark, 1996;Stocco et al, 2005). It is now clear that changes in StAR transcription, protein and activity account for increases in P4 production in response to trophic stimulation and acute decreases in P4 production after luteolytic treatments (Diaz et al, 2002).…”

Section: Factors Regulating Circulating P4 Concentrationsmentioning

confidence: 99%

Physiological and practical effects of progesterone on reproduction in dairy cattle

Wiltbank

Souza

Carvalho

et al. 2014

Animal

175

114

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The discovery of progesterone (P4) and elucidation of the mechanisms of P4 action have an important place in the history of endocrinology and reproduction. Circulating P4 concentration is determined by a balance between P4 production, primarily by the corpus luteum (CL), and P4 metabolism, primarily by the liver. The volume of luteal tissue and number and function of large luteal cells are primary factors determining P4 production. Rate of P4 metabolism is generally determined by liver blood flow and can be of critical importance in determining circulating P4 concentrations, particularly in dairy cattle. During timed artificial insemination (AI) protocols, elevations in P4 are achieved by increasing number of CL by creating accessory CL or by supplementation with exogenous P4. Dietary manipulations can also alter circulating P4, although practical methods to apply these techniques have not yet been reported. Elevating P4 before the timed AI generally decreases double ovulation and increases fertility to the timed AI. Near the time of AI, slight elevations in circulating P4, possibly due to inadequate luteal regression, can dramatically reduce fertility. After AI, circulating P4 is critical for embryo growth and establishment and maintenance of pregnancy. Many studies have attempted to improve fertility by elevating P4 after timed AI. Our recent meta-analysis and manipulative study indicated small fertility benefits (3% to 3.5%) mostly in primiparous cows. Thus, previous research has provided substantial insight into mechanisms regulating circulating P4 concentrations and actions. Understanding this prior research can focus future research on P4 manipulation to improve reproductive success. Keywords: progesterone, lactating dairy cows, fertility ImplicationsThis manuscript reviews effects of circulating progesterone (P4) on dairy cattle reproduction. Various methods to elevate P4 during growth of the preovulatory follicular wave have been shown to increase pregnancies/ artificial insemination (AI) and reduce double ovulation, providing methods to improve fertility and reduce twinning rate in lactating dairy cattle. Conversely, very low concentrations of P4 near AI are needed to optimize fertility. Finally, elevations of P4 after AI can impact embryonic development and also may elevate fertility. Thus, innovative strategies to optimize circulating P4 concentrations during selected reproductive periods enhance our management tools for improving reproductive efficiency of lactating dairy cows. Discovery of Progesterone (P4)The discovery of P4 begins with a clear description by Regnier deGraaf (1641-1673) of the corpus luteum (CL), calling them 'globules' and correctly surmising (for rabbits) that 'the number of globules equals the number of offspring from a particular mating ' (deGraaf, 1672 in (Jocelyn andSetchell, 1972)). A key discovery came in the laboratory of Gustav Born , an excellent histologist, who observed that the CL was a ductless gland and correctly advanced the idea that it was a gland of internal sec...

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Section: Factors Regulating Circulating P4 Concentrationsmentioning

confidence: 99%

Physiological and practical effects of progesterone on reproduction in dairy cattle

Wiltbank

Souza

Carvalho

et al. 2014

Animal

175

114

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“…2). HMGR and CYP11A1 expressions are rate-limiting steps in steroidogenic pathway (Stocco and Clark 1996). Transcription levels of HMGR and CYP11A1 were not significantly altered upon exposure to TBC.…”

Section: Discussionmentioning

confidence: 85%

Effects of tris(2,3-dibromopropyl) isocyanurate on steroidogenesis in H295R cells

Pan

Wang

et al. 2016

Environ Earth Sci

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Tris(2,3-dibromopropyl) isocyanurate (TBC) is widely used in polymer products. It is ubiquitously found in environmental matrices. Previous studies have shown that TBC has potential endocrine-disrupting effects on aquatic organisms. However, the effects on adrenocortical function and the underlying mechanisms are not well characterized. In present study, the H295R cell line was employed to investigate the potential endocrine-disrupting action of TBC. TBC inhibited basal and forskolin-induced sex hormone production but did not exhibit cytotoxicity. The expression of the steroidogenic genes, StAR, 3bHSD2, CYP17, CYP21, CYP19, HMGR, 17bHSD1, 17bHSD4 and CYP11A, was not changed upon TBC exposure. However, the cAMP inducer forskolin strongly induced the expression of all these genes, except for HMGR, 17bHSD1 and 17bHSD4. TBC blocked forskolin-induced StAR, 3bHSD2, CYP17, CYP21 and CYP19 mRNA expression. Our results indicate that TBC can inhibit sex hormone biosynthesis due to the interference with steroidogenic gene transcription in activated condition.

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“…However, because fish oil was not the dietary lipid supplement in that instance, the recent reports by Wonnacott et al (2010) and Hughes et al (2011) are more pertinent to the current study. Among their findings, Hughes et al (2011) indicated that n-3 PUFAs specifically enhance progesterone synthesis by thecal cells of ovine follicles and that this is associated with increased StAR transcript expression, notable because the translated steroidogenic acute regulatory protein is an important facilitator of cholesterol transport to mitochondrial membranes, the rate-limiting step in progesterone biosynthesis (Stocco and Clark, 1996;Niswender, 2002). Further reassurance that fish oil was unlikely to have compromised luteal-phase progesterone production in the present study derives from the fact that n-3 fatty acids in fish oil appear able to confer an additional benefit of reducing the synthesis of the uterine antiluteolytic agent, PGF 2α , even when luteal-phase progesterone concentrations are low (Wamsley et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Impact of contrasting fish oil concentrations in the diet on ovine embryo development <i>in vivo</i> and of corresponding diet-specific derivative sera during <i>in vitro</i> culture

McEvoy¹,

Önal²,

Speake³

et al. 2012

J. Anim. Feed Sci.

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In the first of two experiments, numbers of ovulations and day 5 embryo yields were unaffected by fish oil (0, 3 or 6% w/w) in ewe diets; oestradiol concentrations and numbers of large ovarian follicles were increased. Fish oil tended to suppress embryo development and limit blastocyst diameter and cell number but not protein synthesis. In the second experiment IVF-derived embryos were cultured in medium supplemented with foetal calf serum (FCS) or, as in vitro equivalents to Experiment 1, serum from ewes fed rations supplemented with 0 (C), 3 (3F) or 6 (6F)% fish oil. Cleavage rates were not affected by serum source. More Grade 1 to 1.5 blastocysts were produced when using 3F serum (32% of blastocysts) than with C (27%; ns) or 6F (16%; P<0.05) or FCS (10%; P<0.005). It is suggested that at less than 3% inclusion in the diet of ewes, there may be beneficial effects of fish oil fatty acids on embryo production in vivo and of the corresponding ewe serum during in vitro culture. Higher concentrations are counter-productive.

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Role of the steroidogenic acute regulatory protein (StAR) in steroidogenesis

Cited by 242 publications

References 106 publications

Physiological and practical effects of progesterone on reproduction in dairy cattle

Physiological and practical effects of progesterone on reproduction in dairy cattle

Effects of tris(2,3-dibromopropyl) isocyanurate on steroidogenesis in H295R cells

Impact of contrasting fish oil concentrations in the diet on ovine embryo development <i>in vivo</i> and of corresponding diet-specific derivative sera during <i>in vitro</i> culture

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