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Angiotensin Peptides Stimulate Phosphoinositide Breakdown and Prolactin Release in Anterior Pituitary Cells in Culture*
- Source :
- Endocrinology. 118:233-238
- Publication Year :
- 1986
- Publisher :
- The Endocrine Society, 1986.
-
Abstract
- We investigated the effects of angiotensin peptides on the breakdown of specific membrane phospholipids, the inositol lipids, in anterior pituitary cells in culture, measuring the water-soluble products (inositol phosphates) produced during the cleavage of phosphoinositides by phospholipase C. Both angiotensin II and angiotensin I in the presence of 10 mM LiCl potently increased, in a concentration-dependent manner, total [3H]inositol phosphate and PRL release in cultured rat anterior pituitary cells. The release of LH, TSH, or GH was not significantly enhanced by the peptides. The effect on inositol phosphate accumulation was significant at 0.01 nM, and maximal stimulation (approximately 5-fold increase) occurred at 10 nM, with an ED50 of about 0.3 nM. The stimulatory effects of both angiotensin II and angiotensin I were antagonized by the receptor antagonists saralasin and Sar1,Ile8-angiotensin II. Moreover, 1 microM captopril, an inhibitor of angiotensin-converting enzyme, antagonized the effects of 0.1 and 1 nM angiotensin I, suggesting that the effect of angiotensin I on phosphoinositide breakdown and PRL release is dependent on prior conversion of angiotensin I to angiotensin II. The effect of angiotensin II was very rapid. Fractionation of the water-soluble inositol phosphates showed that angiotensin II significantly increased inositol bisphosphate and inositol triphosphate at 10 sec, whereas inositol monophosphate was increased only after 40 sec. These data indicate that in the pituitary, and presumably in the lactotroph, the binding of angiotensin II to specific membrane receptors provokes increased polyphosphoinositide hydrolysis, leading to increased production of intracellular messengers, i.e. inositol triphosphate and 1,2-diacylglycerol, responsible for the stimulation of PRL release.
- Subjects :
- Angiotensin receptor
medicine.medical_specialty
Angiotensins
Captopril
Inositol Phosphates
Biology
Pituitary neoplasm
1-Sarcosine-8-Isoleucine Angiotensin II
Phosphatidylinositols
chemistry.chemical_compound
Endocrinology
Anterior pituitary
Pituitary Gland, Anterior
Internal medicine
medicine
Animals
Pituitary Neoplasms
Inositol
Inositol phosphate
Cells, Cultured
chemistry.chemical_classification
Receptors, Angiotensin
Angiotensin II
Rats, Inbred Strains
Angiotensin-converting enzyme
Prolactin
Rats
Kinetics
medicine.anatomical_structure
chemistry
biology.protein
Female
Angiotensin I
Saralasin
Subjects
Details
- ISSN :
- 19457170 and 00137227
- Volume :
- 118
- Database :
- OpenAIRE
- Journal :
- Endocrinology
- Accession number :
- edsair.doi.dedup.....e1c62acc1aebdbc1580861566c2d55b1