title: Unusual arrangement of agranular endoplasmic reticulum in the interstitial cells of the cat ovary.
abstract: An unusual arrangement of agranular endoplasmic reticulum in the interstitial cells of the cat ovary is described. The structural unit of this arrangement in cross section consists of five membranous sacs (800 to 900 A long and 250 to 350 A wide) radially coverging toward a microtubule. The sacs are separated from each other by three angles of 60 degrees and two of 90 degrees. In longitudinal section, the sacs appear to be long parallel cisternae. The geometric, radial arrangement seems to arise from a gradual incurvation and convergence of parallel units in these membranes. The microtubules may act as guides for the polarization and resulting unusual arrangement of the membranes. The purpose of such polarization may be related to a change from protein to steriod synthesis in these cells.
mesh_terms: D000818:Animals; D001699:Biometry; D002415:Cats; D003584:Cytological Techniques; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure*; D005260:Female; D008854:Microscopy, Electron; D008867:Microtomy; D008870:Microtubules / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D010053:Ovary / Q000166:cytology*; D014176:Protein Biosynthesis; D013256:Steroids / Q000096:biosynthesis
chemical_list: D013256:Steroids