Biomaterial Database

Early effects of luteinizing hormone on mitochondrial phosphoinositides in ovarian follicles. 1987

M J Dimino, and J Snitzer, and T A Noland

It is not clear if luteinizing hormone (LH) stimulates breakdown as well as synthesis of phosphoinositides in ovarian tissue. Possibly, LH stimulation results in hydrolysis of ovarian phosphoinositides in discrete subcellular compartments while increasing their synthesis at other sites. To investigate this hypothesis, we determined the effects of LH on phosphoinositide metabolism in whole homogenates and mitochondria of ovarian follicles. Medium (3-7 mm) follicles from porcine ovaries were preincubated for 2 h in phosphate (PO4)-free medium with 32PO4, and incubated without or with LH (1 microgram/ml). Phosphatidylinositol (PI) and related compounds, phosphatidic acid (PA), phosphatidylinositol phosphate (PIP) and phosphatidylinositol bisphosphate (PIP2), accounted for 40% of the radiolabeled phospholipids in whole homogenates and over 60% in mitochondria from preincubated follicles. After 5 min, LH caused a significant decrease in radiolabeling of PIP2 and PIP in mitochondria, but not in whole homogenates. Luteinizing hormone increased radiolabeling of PIP2, PIP, PI and PA within 10 min in whole homogenates, and within 20 to 30 min in mitochondria. This delayed increase in radiolabeling of mitochondrial phosphoinositides after LH treatment was accompanied by decreases in PIP2, PIP and PI radiolabeling in whole homogenates. Follicles also were preincubated for 4 h with [3H]inositol, then for 15 min with 10 mM LiCl (an inhibitor of inositol phosphate hydrolysis). Inositol phosphate accumulation in 30 min was 2.7 times higher in homogenates of LH-treated follicles then in untreated follicles. Also, LH significantly decreased inositol bisphosphate, but did not change inositol trisphosphate accumulation. Accumulation of inositol phosphates in mitochondria was not measurable.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
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
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D010712	Phosphatidic Acids	Fatty acid derivatives of glycerophosphates. They are composed of glycerol bound in ester linkage with 1 mole of phosphoric acid at the terminal 3-hydroxyl group and with 2 moles of fatty acids at the other two hydroxyl groups.	Ammonium Phosphatidate,Diacylglycerophosphates,Phosphatidic Acid,Acid, Phosphatidic,Acids, Phosphatidic,Phosphatidate, Ammonium
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
D005260	Female		Females
D006080	Ovarian Follicle	An OOCYTE-containing structure in the cortex of the OVARY. The oocyte is enclosed by a layer of GRANULOSA CELLS providing a nourishing microenvironment (FOLLICULAR FLUID). The number and size of follicles vary depending on the age and reproductive state of the female. The growing follicles are divided into five stages: primary, secondary, tertiary, Graafian, and atretic. Follicular growth and steroidogenesis depend on the presence of GONADOTROPINS.	Graafian Follicle,Atretic Follicle,Ovarian Follicles,Atretic Follicles,Follicle, Atretic,Follicle, Graafian,Follicle, Ovarian,Follicles, Atretic,Follicles, Graafian,Follicles, Ovarian,Graafian Follicles
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D018129	Phosphatidylinositol Phosphates	Phosphatidylinositols in which one or more alcohol group of the inositol has been substituted with a phosphate group.	Polyphosphoinositides,Phosphatidyl Inositol Phosphates,Polyphosphoinositide,Inositol Phosphates, Phosphatidyl,Phosphates, Phosphatidyl Inositol,Phosphates, Phosphatidylinositol