Biomaterial Database

Modulation of luteinizing hormone-stimulated inositol phosphate accumulation by phorbol esters in bovine luteal cells. 1992

J S Davis

Department of Veterans Affairs Medical Center, Women's Research Institute, Wichita, Kansas.

The present studies were conducted to evaluate the effects of protein kinase C activators on the inositol phospholipid-phospholipase C second messenger system in isolated bovine luteal cells. This report describes the effects of phorbol esters on inositol phosphate accumulation in LH- and prostaglandin F2 alpha (PGF2 alpha)-stimulated bovine luteal cells. Corpora lutea of early pregnancy were dispersed with collagenase and luteal cells were prelabelled for 3 h with [3H]inositol. Inositol phosphates produced in response to LH or PGF2 alpha were analyzed by ion exchange column chromatography. The tumor promoter and protein kinase C activator 12-O-tetradecanolyphorbol 13-acetate (TPA) had no effect on basal levels of inositol phosphates but inhibited LH-stimulated accumulation of inositol mono-, bis-, and trisphosphates by 72%, 68%, and 65%, respectively. TPA reduced the response to maximally effective concentrations of LH and tripled the concentrations of LH required to evoke half-maximal accumulation of inositol mono-, bis-, trisphosphates. The inhibitory effects of TPA were rapid (5 min) whether added before or after treatment with LH. Treatment with TPA also reduced (58%) the initial phase of intracellular calcium mobilization in LH-treated cells. The inhibitory effects of TPA were not associated with acute reductions in [3H]inositol incorporation, [3H]inositol phospholipid levels, cAMP levels, or progesterone accumulation in control or LH-stimulated luteal cells. The effects of phorbol esters were concentration dependent and specific for active tumor promoters with 10-50 nM TPA producing maximal inhibitory effects. A synthetic diacylglycerol, 1-oleyl-2-acetylglycerol, mimicked the inhibitory effects of TPA. In contrast, pretreatment with a physiological activator of protein kinase C, PGF2 alpha, had no effect on LH-stimulated inositol phosphate accumulation. The inhibitory effects of TPA could not be explained by a generalized inhibition of phospholipase C or G-proteins since the accumulation of inositol phosphates in PGF2 alpha- and NaF-treated cells was not inhibited by TPA. These results demonstrate that tumor promoting phorbol esters modulate the inositol phospholipid-phospholipase C transmembrane signaling system in LH-stimulated bovine luteal cells. The results suggest that phorbol esters may alter the coupling of the LH-receptor complex to phospholipase C. These findings implicate protein kinase C in the regulation of transmembrane signaling in the bovine corpus luteum.

UI	MeSH Term	Description	Entries
D007294	Inositol	An isomer of glucose that has traditionally been considered to be a B vitamin although it has an uncertain status as a vitamin and a deficiency syndrome has not been identified in man. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1379) Inositol phospholipids are important in signal transduction.	Myoinositol,Chiro-Inositol,Mesoinositol,Chiro Inositol
D007295	Inositol Phosphates	Phosphoric acid esters of inositol. They include mono- and polyphosphoric acid esters, with the exception of inositol hexaphosphate which is PHYTIC ACID.	Inositol Phosphate,Phosphate, Inositol,Phosphates, Inositol
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007986	Luteinizing Hormone	A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.	ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D008184	Luteal Cells	PROGESTERONE-producing cells in the CORPUS LUTEUM. The large luteal cells derive from the GRANULOSA CELLS. The small luteal cells derive from the THECA CELLS.	Lutein Cells,Granulosa-Luteal Cells,Granulosa-Lutein Cells,Large Luteal Cells,Small Luteal Cells,Theca-Luteal cells,Theca-Lutein Cells,Cell, Granulosa-Luteal,Cell, Granulosa-Lutein,Cell, Large Luteal,Cell, Luteal,Cell, Lutein,Cell, Small Luteal,Cell, Theca-Lutein,Cells, Granulosa-Luteal,Cells, Granulosa-Lutein,Cells, Large Luteal,Cells, Luteal,Cells, Lutein,Cells, Small Luteal,Cells, Theca-Lutein,Granulosa Luteal Cells,Granulosa Lutein Cells,Granulosa-Luteal Cell,Granulosa-Lutein Cell,Large Luteal Cell,Luteal Cell,Luteal Cell, Large,Luteal Cell, Small,Luteal Cells, Large,Luteal Cells, Small,Lutein Cell,Small Luteal Cell,Theca Luteal cells,Theca Lutein Cells,Theca-Luteal cell,Theca-Lutein Cell,cell, Theca-Luteal,cells, Theca-Luteal
D010716	Phosphatidylinositols	Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids.	Inositide Phospholipid,Inositol Phosphoglyceride,Inositol Phosphoglycerides,Inositol Phospholipid,Phosphoinositide,Phosphoinositides,PtdIns,Inositide Phospholipids,Inositol Phospholipids,Phosphatidyl Inositol,Phosphatidylinositol,Inositol, Phosphatidyl,Phosphoglyceride, Inositol,Phosphoglycerides, Inositol,Phospholipid, Inositide,Phospholipid, Inositol,Phospholipids, Inositide,Phospholipids, Inositol
D010738	Type C Phospholipases	A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.	Lecithinase C,Phospholipase C,Phospholipases, Type C,Phospholipases C
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011374	Progesterone	The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.	Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation