Regulation of cytochrome P450scc synthesis and activity in the ovine corpus luteum

Belfiore, Carol J.; Hawkins, D. E.; Wiltbank, Milo C.; Niswenders, Gordon D.

doi:10.1016/0960-0760(94)90041-8

Cited by 23 publications

(18 citation statements)

References 38 publications

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“…Collectively, these data suggest that increased plasma concentrations of progesterone are a result of an LH-dependent mechanism downstream of mRNA (e.g. protein stability and/or enzyme activity; Belfiore et al 1994). An alternative explanation is that increased progesterone concentrations are of follicular origin.…”

Section: Discussionmentioning

confidence: 99%

Levels of messenger RNA encoding ovarian receptors for FSH and LH in cattle during superovulation with equine chorionic gonadotrophin versus FSH

Soumano

Lussier²,

Price³

1998

Journal of Endocrinology

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This study tested the hypothesis that luteal LH receptor (LHr) and follicular LHr and FSH receptor (FSHr) steadystate mRNA levels are greater during superovulation with equine chorionic gonadotrophin (eCG) compared with that with FSH. Heifers were stimulated with eCG (n=10) or FSH (n=10), and ovaries were recovered the day before and at 12 and 24 h after luteolysis was induced with prostaglandin F 2 (PGF 2 ). Total RNA was purified from individual follicles and corpora lutea. Steady-state levels of LHr and FSHr mRNA were assessed by slot blot analysis employing homologous cDNA probes. There were no differences in luteal LHr between FSH-and eCGstimulated animals before luteolysis, and hybridization signals were detected in only one of six animals by 12 h after injection of PGF 2 . After PGF 2 injection, steadystate levels of follicular LHr were 4-fold lower (P<0·05) and follicular FSHr mRNA levels were 2·4-fold lower (P<0·05) in eCG-compared with FSH-treated cattle. In eCG-treated animals, induction of luteolysis led to a significant increase in follicular LHr mRNA levels (P<0·01) and a significant decrease in follicular FSHr mRNA levels (P<0·01). There was no such effect of luteolysis in FSH-treated animals. We conclude that superovulation with eCG, compared with FSH, results in lower follicular levels of LHr and FSHr mRNA but does not affect luteal LHr mRNA levels.

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Section: Discussionmentioning

confidence: 99%

Levels of messenger RNA encoding ovarian receptors for FSH and LH in cattle during superovulation with equine chorionic gonadotrophin versus FSH

Soumano

Lussier²,

Price³

1998

Journal of Endocrinology

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“…Luteolysis is a complex process involving changes in expression of multiple genes in at least 3 cell types (large and small steroidogenic cells and endothelial cells) [1][2][3][4][5][6][7][8][9][10][11]. There are reports that either natural luteolysis or treatment with PGF 2 decrease mRNA encoding gene products that regulate steroidogenesis [1][2][3][4], increase mRNA for stressrelated or apoptotic genes [5][6][7], and increase mRNA for factors involved in immune response [8][9][10].…”

Section: Introductionmentioning

confidence: 97%

“…There are reports that either natural luteolysis or treatment with PGF 2 decrease mRNA encoding gene products that regulate steroidogenesis [1][2][3][4], increase mRNA for stressrelated or apoptotic genes [5][6][7], and increase mRNA for factors involved in immune response [8][9][10]. Recently, it was found that PGF2, also increased mRNA encoding enzymes that stimulate PGF 2 , production in the ovine corpus luteum (CL) 112].…”

Section: Introductionmentioning

confidence: 99%

Prostaglandin F2α Regulates Distinct Physiological Changes in Early and Mid-Cycle Bovine Corpora Lutea1

Tsai

Wiltbank

1998

Biology of Reproduction

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172

113

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Prostaglandin (PG) F2alpha is the primary luteolysin in most species. A single treatment with PGF2alpha will cause regression of the mid-cycle but not the early-cycle (Days 1-5 after estrus) bovine corpus luteum (CL) despite the presence of similar concentrations of high-affinity PGF2alpha receptors (FP receptors). This study was designed to determine whether PGF2alpha activated similar intracellular processes in early- and mid-cycle CL. Cows received saline or 25 mg PGF2alpha injection (i.m.; n = 6/group) on Day 4 or 11 after onset of the LH surge (induced by GnRH injection), and CL were collected at 4 h after treatment. As expected, CL volumes and luteal weights were not different at 4 h after PGF2alpha treatment. Luteal vitamin C concentration and steady-state concentrations of mRNA for 3beta-hydroxysteroid dehydrogenase and for FP receptor were decreased by 4 h in both Day 4 and 11 CL treated with PGF2alpha (p < 0.05). These results demonstrate clear actions of PGF2alpha in the early CL. In contrast, steady-state concentrations of mRNA encoding PG G/H synthase-2 (PGHS-2) were increased by treatment with PGF2alpha in mid-cycle CL but decreased by PGF2alpha in early-cycle CL (p < 0.05). In addition, treatment of mid-cycle but not early-cycle cows with PGF2alpha decreased luteal and serum progesterone concentrations by 4 h (p < 0.05). In summary, PGF2alpha clearly exerts actions in both early- and mid-cycle bovine CL. The lack of PGF2alpha-induced luteolysis in the early CL may be due to specific changes in gene expression, especially PGHS-2, that may prevent intraluteal PGF2alpha production and possibly other key luteolytic processes.

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“…Long-term (4 h or more) application of steroidogenic stimuli has consistently been found to alter expression of protein and message for P450 scc and other enzymes involved in steroidogenesis, in a transcription-dependent manner [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In contrast, acute stimulation of steroidogenesis has been determined to be independent of transcription, despite a requirement for de novo protein synthesis [18][19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 98%

“…This step is critical for steroid hormone synthesis, and the high K m (50 M) of the enzyme [9] suggests that when steroidogenesis is stimulated the substrate is present in relatively high concentrations at the inner mitochondrial membrane, where the enzyme is situated.…”

Section: Introductionmentioning

confidence: 99%

Prostaglandin F2α Induces a Rapid Decline in Progesterone Production and Steroidogenic Acute Regulatory Protein Expression in Isolated Rat Corpus Luteum Without Altering Messenger Ribonucleic Acid Expression1

Fiedler

Plouffe

Hales

et al. 1999

Biology of Reproduction

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With interest in steroidogenic acute regulatory protein (StAR) involvement in the luteolytic process, we studied changes in serum progesterone levels and the concomitant expression of StAR mRNA and protein (37-, 32-, and 30-kDa forms) in postovulatory Day 7 corpora lutea (CL) isolated from rats 1 h after injection with prostaglandin F(2alpha) (PGF(2alpha), n = 6) or saline (n = 6). Serum progesterone levels were determined by RIA, StAR and beta-actin mRNA expression by Northern analysis, and StAR and beta-actin protein expression by Western analysis. Adrenal, brain, and spleen from control animals were used as positive and negative controls for StAR expression. Scanning optical densitometry measurements were standardized by dividing the signal strength from each StAR autoradiogram lane by that from the corresponding beta-actin autoradiogram lane. ANOVA was used for significance testing, with alpha set at 0.05. The 37-, 32-, and 30-kDa forms of StAR protein were expressed in all adrenal samples, whereas only the 37- and 30-kDa forms were found in CL. Serum progesterone levels and expression of the 30-kDa and 37-kDa forms of the StAR protein in CL were all found to be significantly lower in the PGF(2alpha)-treated than the saline-treated group. StAR mRNA expression was not significantly different in the saline- and PGF(2alpha)-treated rats. The rapid decline in StAR protein expression that accompanies PGF(2alpha) induced luteolysis, therefore, does not result from significant decline in mRNA expression.

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Regulation of cytochrome P450scc synthesis and activity in the ovine corpus luteum

Cited by 23 publications

References 38 publications

Levels of messenger RNA encoding ovarian receptors for FSH and LH in cattle during superovulation with equine chorionic gonadotrophin versus FSH

Levels of messenger RNA encoding ovarian receptors for FSH and LH in cattle during superovulation with equine chorionic gonadotrophin versus FSH

Prostaglandin F2α Regulates Distinct Physiological Changes in Early and Mid-Cycle Bovine Corpora Lutea1

Prostaglandin F2α Induces a Rapid Decline in Progesterone Production and Steroidogenic Acute Regulatory Protein Expression in Isolated Rat Corpus Luteum Without Altering Messenger Ribonucleic Acid Expression1

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