Interaction of angiotensin II with dispersed cells from the anterior pituitary of the male rat
Membranes from 6-week-old male rat anterior pituitaries possess saturable binding sites for angiotensin II (AII; Kd . approximately 2 X 10(-9) M). The binding is specific since it can be competed for with (Sar1,Leu8)AII and is unaffected by the presence of insulin or cholecystokinin octapeptide at nanomolar concentrations. To find out which cell types specifically interact with AII, rat anterior pituitaries were enzymatically dispersed and exposed to (/sup 125/I)iodo-AII (2 nM) in the absence or presence of (Sar1,Leu8)AII (400 nM). The cells were then washed free of unbound ligand and processed for light and electron microscopic autoradiography. Distribution of autoradiographic grains revealed that three cell types were specifically labeled with (/sup 125/I)iodo-AII, namely mammotrophs, corticotrophs, and presumptive thyrotrophs. These cells were all labeled in the presence of (/sup 125/I)iodo-AII alone (experimentals), whereas only 10-30% of them were labeled when 400 nM (Sar1,Leu8)AII was included in the binding reaction (controls). The number of grains over the labeled cells in the controls was 20% of that found in the experimental cells. These results may imply that AII can regulate anterior pituitary functions under physiological conditions by interacting directly with its secretory cells.
- Research Organization:
- Yale Univ. School of Medicine, New Haven, CT
- OSTI ID:
- 6538593
- Journal Information:
- Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 114:6; ISSN ENDOA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
ANIMAL CELLS
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
ENDOCRINE GLANDS
GLANDS
GLOBULINS
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
MICROSCOPY
NUCLEI
ODD-EVEN NUCLEI
OPTICAL MICROSCOPY
ORGANIC COMPOUNDS
ORGANS
PHYSIOLOGY
PITUITARY GLAND
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
VASOCONSTRICTORS
VERTEBRATES