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Control of bovine placental progesterone synthesis: Roles of cholesterol availability and calcium-activated systems
- Source :
- Journal of Steroid Biochemistry. 29:21-25
- Publication Year :
- 1988
- Publisher :
- Elsevier BV, 1988.
-
Abstract
- It was previously reported that dispersed bovine placentome secretes progesterone and that the steroidogenic activity of these cells is stimulated by a calcium-mediated, cyclic nucleotide independent mechanism. In the present study, the influence of substrate availability was explored and the roles of calmodulin and protein kinase C in progestin production examined. Incubation of dispersed fetal cotyledon cells with 25-hydroxycholesterol (25-OH-C), a soluble sterol which readily enters cells and is metabolized to steroid hormones, increased progesterone secretion in a dose-dependent manner. The response to 25-OH-C was dependent on the extracellular calcium concentration. Methyl isobutyl xanthine (MIX) alone also increased pregnenolone as well as progesterone secretion, and the combination of 25-OH-C and MIX stimulated progesterone secretion was inhibited by trifluoperazine. The phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), caused no major effects on steroidogenesis but the stimulatory effects of MIX or the ionophore A23187 were enhanced in its presence. These findings suggest that (1) basal progesterone secretion by fetal cotyledon cells is limited by cholesterol availability; (2) MIX increases steroidogenesis in part by increasing the synthesis of pregnenolone, but its actions are expressed independently of cholesterol availability; (3) both calmodulin and protein kinase C may participate in the modulation of bovine placental steroidogenesis.
- Subjects :
- medicine.medical_specialty
Calmodulin
Placenta
chemistry.chemical_element
Biology
Calcium
Biochemistry
Cyclic nucleotide
chemistry.chemical_compound
Endocrinology
Pregnancy
1-Methyl-3-isobutylxanthine
Internal medicine
Progesterone receptor
medicine
Animals
Drug Interactions
Calcimycin
Progesterone
Protein kinase C
Progesterone secretion
Hydroxycholesterols
Trifluoperazine
Sterol
Cholesterol
chemistry
biology.protein
Pregnenolone
Tetradecanoylphorbol Acetate
Cattle
Female
medicine.drug
Subjects
Details
- ISSN :
- 00224731
- Volume :
- 29
- Database :
- OpenAIRE
- Journal :
- Journal of Steroid Biochemistry
- Accession number :
- edsair.doi.dedup.....f7cb5839d8fcb0851d629b804b18c3ad