Effects of prostaglandin F2 alpha and a gonadotropin-releasing hormone agonist on inositol phospholipid metabolism in isolated rat corpora lutea of various ages
The sensitivity of rat corpora lutea to luteolytic agents increases with luteal age. We examined the effect of prostaglandin F2 alpha (PGF2 alpha) and (D-Ala6,Des-Gly10)GnRH ethylamide (GnRHa) on inositol phospholipid metabolism in day 2 and day 7 corpora lutea from PMSG-treated rats. Isolated corpora lutea were incubated with 32PO4 or (3H)inositol and were treated with LH, PGF2 alpha, or GnRHa. Phospholipids were purified by TLC, and the water-soluble products of phospholipase-C activity (inositol phosphates) were isolated by ion exchange chromatography. In day 2 corpora lutea, PGF2 alpha, (10 microM) and GnRHa (100 ng/ml) significantly increased 32PO4 incorporation into phosphatidic acid (PA) and phosphatidylinositol (PI), but not into other fractions. LH provoked slight increases in PA. Results were similar with 30 min of prelabeling or simultaneous addition of 32PO4 and stimulants. In other experiments, PGF2 alpha and GnRHa provoked rapid increases (1-5 min) in the accumulation of inositol mono-, bis-, and trisphosphates. LH did not significantly increase inositol phosphate accumulation, but stimulated cAMP accumulation in 2-day-old corpora lutea. Inositol phospholipid metabolism was increased in day 7 corpora lutea compared to that in day 2 corpora lutea. This increase was associated with increased incorporation of 32PO4 into PA and PI and increased accumulation of (3H)inositol phosphates. In day 7 corpora lutea, which are very sensitive to the luteolytic effect of PGF2 alpha, the PG-induced increase in PA labeling was small and inconsistent, whereas PI labeling was unaffected in 30-min incubations. GnRHa was without effect in such corpora lutea. LH, PGF2 alpha, or GnRHa did not increase inositol phosphate accumulation in 7-day-old corpora lutea. These studies demonstrate that the transformation of young (day 2) to mature (day 7) corpora lutea is associated with an increase in luteal inositol phospholipid metabolism.
- Research Organization:
- Technion-Israel Institute of Technology, Haifa
- OSTI ID:
- 6924495
- Journal Information:
- Endocrinology; (United States), Vol. 123:2
- Country of Publication:
- United States
- Language:
- English
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LH
BIOCHEMICAL REACTION KINETICS
PHOSPHOLIPIDS
METABOLISM
PROSTAGLANDINS
COMPARATIVE EVALUATIONS
ENZYME ACTIVITY
INOSITOL
ION EXCHANGE CHROMATOGRAPHY
LIPASE
PHOSPHATES
PHOSPHORUS 32
RATS
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOHYDRATES
CARBOXYLESTERASES
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
ESTERS
GONADOTROPINS
HORMONES
HYDROLASES
INOSITOLS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
MAMMALS
MONOSACCHARIDES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PITUITARY HORMONES
RADIOISOTOPES
REACTION KINETICS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
VERTEBRATES
550501* - Metabolism- Tracer Techniques