Some aspects of the comparative ultrastructure of interrenal tissue in amphibians, reptiles, and birds
MetadataShow full item record
The electron microscope was used to study comparatively the interrenal tissue of species selected from three vertebrate classes which were chosen as representatives of a particular segment of the evolutionary tree. Certain similarities exist in the interrenals of the species chosen, inasmuch as a similar cordal arrangement of cortical cells, as well as an intermingling of chromaffin and interrenal tissue have been described. In addition, the interrenal cells have been shown to be under the influence of the pituitary gland in all vertebrates. The bases for comparison of the species selected are evolutionary ties, the fact that the interrenal cells produce certain hormones common to all classes, and the fact that the enzymes necessary for hormone production reside in or on the mitochondria. Nine species of animals were used: three amphibians, four reptiles, and two birds, each representing a different order. Several fixatives were tried, but the one most frequently used was a phosphate buffered 1% osmium solution (Millonig, 1962) with modifications to suit the pH and osmolarity of the animal involved. Tissues were fixed for 1/2 to 1 1/2 hours at 4°C. Dehydration was effected in graded acetenes and the material was embedded in either Vestopal W, Araldite 502 or Maraglas 655. Vestopal W gave the most contrast and stability, but was the most difficult to section. Sectioning was accomplished with a Leitz, Hnxley, or PorterBlum microtome with a glass knife. Sections of gold or silver color were chosen for electron microscopy, which were 900 - 1500 A thick (Peachey, 1958). Sections were also cut 1u thick and stained with 1% aqueous methylene blue for light microscopy. The thin sections were picked up on slotted, uncoated grids and routinely stained with phosphotungstic acid. Some were also stained with lead hydroxide or uranyl acetate. The grids were then viewed and photographed with an RCA-EMU-2B or with a Siemens Elmiskop I electron microscope [TRUNCATED]
Thesis (Ph.D.)--Boston University
RightsBased on investigation of the BU Libraries' staff, this work is free of known copyright restrictions.