Evidence for selective expression of angiotensin II receptors on atretic follicles in the rat ovary: an autoradiographic study.
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 [125I]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 of 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.
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D004971:Estrus / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D005496:Follicular Atresia; D005498:Follicular Phase; D007457:Iodine Radioisotopes; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000378:metabolism; D010053:Ovary / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D011962:Receptors, FSH / Q000378:metabolism; D014018:Tissue Distribution
D007457:Iodine Radioisotopes; D011945:Receptors, Angiotensin; D011962:Receptors, FSH; D000804:Angiotensin II; D005640:Follicle Stimulating Hormone; D015059:1-Sarcosine-8-Isoleucine Angiotensin II