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Title: Angiotensin II receptors in testes

Abstract

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:
Research Org.:
National Institute of Child Health and Human Development, Bethesda, MD (USA)
OSTI Identifier:
7196268
Resource Type:
Journal Article
Resource Relation:
Journal Name: Endocrinology; (United States); Journal Volume: 122:5
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

Citation Formats

Millan, M.A., and Aguilera, G.. Angiotensin II receptors in testes. United States: N. p., 1988. Web. doi:10.1210/endo-122-5-1984.
Millan, M.A., & Aguilera, G.. Angiotensin II receptors in testes. United States. doi:10.1210/endo-122-5-1984.
Millan, M.A., and Aguilera, G.. Sun . "Angiotensin II receptors in testes". United States. doi:10.1210/endo-122-5-1984.
@article{osti_7196268,
title = {Angiotensin II receptors in testes},
author = {Millan, M.A. and Aguilera, G.},
abstractNote = {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 rat 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.},
doi = {10.1210/endo-122-5-1984},
journal = {Endocrinology; (United States)},
number = ,
volume = 122:5,
place = {United States},
year = {Sun May 01 00:00:00 EDT 1988},
month = {Sun May 01 00:00:00 EDT 1988}
}
  • Specific, high-affinity (K/sub d/ approx. = 0.6 nM), and saturable (3.3 fmol/mg of tissue, wet weight) binding of /sup 125/I-labeled (Sar/sup 1/,Ile/sup 8/)angiotensin II to rat ovarian membranes was observed. Displacement of /sup 125/I-labeled (Sar/sup 1/,Ile/sup 8/)angiotensin II binding to rat ovarian membranes by angiotensin II analogs and fragments resembled the potency order of these compounds on angiotensin II receptors in other tissues. Several unrelated peptides, including follicle-stimulating hormone at 10..mu..M, did not displace ovarian /sup 125/I-labeled (Sar/sup 1/, Ile/sup 8/)angiotensin II binding. Autoradiograms of /sup 125/I-labeled (Sar/sup 1/,Ile/sup 8/)angiotensin II binding to ovarian sections indicated that the angiotensin IImore » receptor binding sites were localized exclusively to a subpopulation of follicles, occurring on the granulosa and theca interna cells. Other follicles were devoid of /sup 125/I-labeled (Sar/sup 1/,Ile/sup 8/)angiotensin II binding sites. Angiotensin II immunoreactive material was also identified in the ovary. The concentration of ovarian Ang II immunoreactivity was 8- to 75-fold greater than that of plasma, was not reduced in bilaterally nephrectomized rats, and was shown by high-pressure liquid chromatographic analysis to be the native angiotensin II octapeptide. The presence of angiotensin II and its receptor binding sites in the ovary suggests a role for angiotensin II as a regulator of ovarian function.« less
  • The presence of components of the renin-angiotensin system in ovaries and testes suggests that angiotensin II (AII) is involved in gonadal function, and thus we sought to characterize receptors for AII in rat and primate gonads. In the testes, autoradiographic studies showed receptors in the interstitium in all species. In rat interstitial cells fractionated by Percoll gradient, AII receptors coincided with hCG receptors indicating that AII receptors are located on the Leydig cells. In Leydig cells and membranes from rat and rhesus monkey prepuberal testes, AII receptors were specific for AII analogues and of high affinity (Kd=nM). During development, AIImore » receptor content in rat testes decreases with age parallel to a fall in the ratio of interstitial to tubular tissue. In the ovary, the distribution of AII receptors was dependent on the stage of development, being high in the germinal epithelium and stromal tissue between five and 15 days, and becoming localized in secondary follicles in 20-and 40-day-old rats. No binding was found in primordial or primary follicles. In rhesus monkey ovary, AII receptors were higher in stromal tissue and lower in granulosa and luteal cells of the follicles. Characterization of the binding in rat and monkey ovarian membranes showed a single class of sites with a Kd in the nmol/L range and specificity similar to that of the adrenal glomerulosa and testicular AII receptors. Receptors for AII were also present in membrane fractions from PMSG/hCG primed rat ovaries. Infusion of AII (25 ng/min) or captopril (1.4 micrograms/min) during the PMSG/hCG induction period had no effect on ovarian weight or AII receptor concentration in the ovaries.« less
  • We analyzed angiotensin II (ANG II) receptors by in vitro autoradiography in selective brain nuclei of control, salt-treated (1% NaCl in drinking water), deoxycorticosterone acetate (DOCA)-treated (DOCA pivalate, 25 mg/kg sc weekly), and DOCA-salt-treated (DOCA + salt treatments) uninephrectomized male Wistar-Kyoto rats. After 4 wk of treatment, only the DOCA-salt group developed hypertension. ANG II binding increased in median preoptic nucleus and subfornical organ of salt- and DOCA-treated rats. DOCA-treated rats also showed increased ANG II binding in paraventricular nucleus. DOCA-salt-treated rats showed higher ANG II binding in nucleus of the solitary tract and area postrema, as well as inmore » the areas mentioned before. Although salt and/or DOCA treatments alone increased ANG II receptors in some brain nuclei, after combined DOCA-salt treatment there was significantly higher ANG II binding in all areas, except the median preoptic nucleus. These results suggest that increased ANG II receptors in selected brain areas may play a role in the pathophysiology of mineralocorticoid-salt experimental hypertension.« less
  • Controversy exists regarding the specific sites within the renal microcirculation affected by angiotensin II (ANG II). Under some conditions, ANG II can elicit direct vasoconstrictor responses in the preglomerular vessels and efferent arterioles. These experiments were designed to evaluate the binding of {sup 125}I-ANG II in preglomerular vessels. Arcuate and interlobular arteries, with attached proximal segments of afferent arterioles, were microdissected from rabbit renal cortexes. A membrane preparation was obtained from the pooled freshly dissected vessels and utilized in an ANG II radioreceptor assay on the same day. The dissociation of bound ANG II was enhanced in the presence ofmore » a nonhydrolyzable analogue of GTP. Linear Scatchard plots were obtained, indicating the presence of a single class of high-affinity binding sites. In conclusion, there is a single class of specific ANG II receptors in preglomerular vessels. The K{sub D} and N are similar, but the binding inhibition potencies of selected ANG analogues differ in renal and extrarenal vascular tissues. Intrarenal vascular receptors also appear to differ from glomerular receptors. Furthermore, these data support the concept that ANG II may affect renal vascular resistance at sites proximal to the distal afferent arterioles.« less
  • Ovarian angiotensin II (Ang II) receptors display a cyclical pattern of variation during the rat estrous cycle. Ang II receptors, estimated by the specific binding of the Ang II receptor antagonist (/sup 125/I)iodo-(Sar1,Ile8) Ang II to ovarian membranes, were lowest at estrus (binding site density (Bmax) = 35 +/- 2 fmol/mg; binding site affinity (KD) = 2.0 +/- 0.2 nM) and highest at diestrus I (Bmax = 59 +/- 3 fmol/mg; KD = 1.6 +/- 0.1 nM). We have previously shown that Ang II receptors in the rat ovary predominantly exist on the granulosa cell layer of a subpopulation ofmore » follicles. Our present studies show that the Ang II receptor-containing follicles in the rat ovary are mainly atretic (approximately 80%) or show signs of early atresia (approximately 15%) during all stages of the estrous cycle. A small number of Ang II receptor-containing follicles were healthy (approximately 5%). In contrast to the Ang II receptor-containing follicles, the FSH receptor-containing follicles were predominantly healthy (greater than 90%). Follicles which contained both Ang II receptors and FSH receptors were mainly early atretic. Since Ang II receptor-containing follicles in the rat ovary were mainly atretic these studies suggest that in the rat Ang II may be a major factor in regulating the function of atretic ovarian follicles.« less