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Title: Angiotensin II receptors in testes

Receptors for angiotensin II (AII) were identified and characterized in testes of rats and several primate species. Autoradiographic analysis of the binding of 125I-labeled (Sar1,Ile8)AII to rat, rhesus monkey, cebus monkey, and human testicular slide-mounted frozen sections indicated specific binding to Leydig cells in the interstitium. In rat collagenase-dispersed interstitial cells fractionated by Percoll gradient, AII receptor content was parallel to that of hCG receptors, confirming that the AII receptors are in the Leydig cells. In rat dispersed Leydig cells, binding was specific for AII and its analogs and of high affinity (Kd, 4.8 nM), with a receptor concentration of 15 fmol/10(6) cells. Studies of AII receptors in rat testes during development reveals the presence of high receptor density in newborn rats which decreases toward the adult age (4934 +/- 309, 1460 +/- 228, 772 +/- 169, and 82 +/- 12 fmol/mg protein at 5, 15, 20, and 30 days of age, respectively) with no change in affinity. At all ages receptors were located in the interstitium, and the decrease in binding was parallel to the decrease in the interstitial to tubular ratio observed with age. AII receptor properties in membrane-rich fractions from prepuberal testes were similar in the ratmore » and rhesus monkey. Binding was time and temperature dependent, reaching a plateau at 60 min at 37 C, and was increased by divalent cations, EGTA, and dithiothreitol up to 0.5 mM. In membranes from prepuberal monkey testes, AII receptors were specific for AII analogs and of high affinity (Kd, 4.2 nM) with a receptor concentration of 7599 +/- 1342 fmol/mg protein. The presence of AII receptors in Leydig cells in rat and primate testes in conjunction with reports of the presence of other components of the renin-angiotensin system in the testes suggests that the peptide has a physiological role in testicular function.« less
Authors:
;
Publication Date:
OSTI Identifier:
7196268
Resource Type:
Journal Article
Resource Relation:
Journal Name: Endocrinology; (United States); Journal Volume: 122:5
Research Org:
National Institute of Child Health and Human Development, Bethesda, MD (USA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ANGIOTENSIN; BIOCHEMICAL REACTION KINETICS; RECEPTORS; CHEMICAL COMPOSITION; AUTORADIOGRAPHY; CELL MEMBRANES; IODINE 125; MAN; MONKEYS; RATS; TEMPERATURE DEPENDENCE; TESTES; TIME DEPENDENCE; ANIMALS; BETA DECAY RADIOISOTOPES; BODY; CARDIOVASCULAR AGENTS; CELL CONSTITUENTS; DAYS LIVING RADIOISOTOPES; DRUGS; ELECTRON CAPTURE RADIOISOTOPES; GLOBULINS; GONADS; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPES; KINETICS; MALE GENITALS; MAMMALS; MEMBRANE PROTEINS; MEMBRANES; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; ORGANS; PRIMATES; PROTEINS; RADIOISOTOPES; REACTION KINETICS; RODENTS; VASOCONSTRICTORS; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques