Ultrastructure of Rat Adenohypophysis. Correlation with Function PDF
Preview Ultrastructure of Rat Adenohypophysis. Correlation with Function
ULTRASTRUCTURE of RAT ADENOHYPOPHYSIS Correlation with Function Allen Costoff Department of Endocrinology Medical College of Georgia Augusta, Georgia ACADEMIC PRESS 1973 New York and London COPYRIGHT © 1973, BY ACADEMIC PRESS, INC. ALL RIGHTS RESERVED. NO PART OF THIS PUBLICATION MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM OR BY ANY MEANS, ELECTRONIC OR MECHANICAL, INCLUDING PHOTOCOPY, RECORDING, OR ANY INFORMATION STORAGE AND RETRIEVAL SYSTEM, WITHOUT PERMISSION IN WRITING FROM THE PUBLISHER. ACADEMIC PRESS, INC. Ill Fifth Avenue, New York, New York 10003 United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. 24/28 Oval Road, London NW1 LIBRARY OF CONGRESS CATALOG CARD NUMBER: 70-154406 PRINTED IN THE UNITED STATES OF AMERICA Preface During the last fifteen years much information has accumulated on the physiology and biochemistry of the anterior pituitary gland. Corticotro- pin, somatotropin, and luteotropin of various species have been purified and studied. Progress is being made in the purification of gonadotropins and thyrotropin. In addition, research on mechanisms of hormone action, on synthesis and release of pituitary hormones, and on actions of various blocking agents on pituitary function is being stressed. These biochemical and physiological findings would be better under- stood with a knowledge of cellular structure. This book not only deals with the ultrastructure of the anterior pituitary in the normal intact rat but also after various treatments and changes in the physiology of the animal. This is the first time that the complete ultrastructure of the rat pituitary is discussed in a single volume. A book of this kind is needed since the rat is usually one of the principal animals used in research. Wherever possible an attempt has been made to coordinate and associate changes in pituitary ultrastructure with physiological aspects. In order that ultrastructural data be placed in proper perspective, literature on the light microscopy of the rat pituitary gland is reviewed and correlated with ultrastructural findings. In addition to ultrastructural data, a method is given for the isolation of various populations of pituitary secretory granules that can be used in experimental endocrinological research. The knowledge obtained from this type of granule fractionation and from assays of different fractions of granules has aided in the identification of cell types in the rat interior pituitary gland. There is a chapter on each of the cell types, including the chromophobe. The often neglected pars tuberalis and pars intermedia of the adeno- hypophysis are discussed and electron micrographs analyzed. Chapters are also included on the chemical and physical properties of the secretory granules and their formation and release. This book should serve as a guide for pituitary ultrastructural studies ix χ Preface in other species and should lead to a greater understanding of physio- logical findings. It should be of value not only to the student and the experienced investigator in endocrinology, anatomy, and pathology but also in physiology, biochemistry, and related disciplines. Much of the experimental work reported here was done in the labora- tories of Professors W. H. McShan and R. K. Meyer. I wish to thank them for their encouragement and for reading the manuscript, and Ann Hyatt for the excellent typing job. Some of the material on granule fractionation and the assay of isolated granule fractions was previously published in the Journal of Cell Biology 43 [3], 1969. We express our thanks to the editors for allowing us to reproduce part of this material. I would also like to thank the staff of Academic Press for their valuable help in the production of this book. This investigation was supported by the National Science Foundation Research Grant No. GB-4963, Public Health Service Training Grant No. 5T1 HD 104-04, Ford Foundation Grant No. 63-505, and the En- docrinology-Reproductive Physiology Training Program, University of Wisconsin. Allen Costoff Abbreviations and Terminology Used in the Text acidophils cells staining with acid stains (light microscopy) somatotropes, mammotropes, corticotropes (elec- tron microscopy) amphophils cells staining with acid and basic stains AF aldehyde fuchsin basophils cells staining with basic stains (light microscopy) thyrotropes and gonadotropes (electron microscopy) chromophils cells containing granules chromophobes cells lacking granules colloid material nondescript material that stains with lead citrate and uranyl acetate corticotrope cell that produces ACTH dense body most likely a lysosome FSH follicle-stimulating hormone gonadotropes cells producing FSH and LH IU International Unit LH luteinizing hormone LTH luteotropin, mammotropin, prolactin, lactogenic hormone luteotrope cell producing LTH M molar mammotrope cell producing LTH microsomes broken-up endoplasmic reticulum mg eq FT milligram equivalent fresh tissue inM millimolar mm millimeter ιημ, millimicron xi xii Abbreviations and Terminology Used in the Text MSH melanocyte-stimulating hormone mu milliunit micron microcuries microgram PAS periodic acid-Schiff reagent PTU propylthiouracil RF releasing factors ÏÏIRNA messenger RNA tRNA transfer RNA somatotrope cell that produces growth hormone STH somatotropin, growth hormone tetrachrome stain PAS, orange G, alcian blue, alizarin blue thyrotrope cell that produces TSH TSH thyrotropin type I cell most prominant cell type of pars intermedia, 350 ηιμ granules type II cell less abundant cell type of the intermedia, smaller granules Abbreviations Used in Electron Micrograph Descriptions CI cilia CO colloid D desmosome DB dense body (lysosome) ER endoplasmic reticulum F follicle G Golgi complex LB light staining body, large bodies LD Lipid droplet M mitochondria MB microbody MT microtubule MV multivesicular body MV microvilli Ρ polysomes R ribosomes RER rough endoplasmic reticulum S secretory granules V vacuolar endoplasmic reticulum VA vacuoles VE vesicles xiii Chapter 1 Introduction The histology of the pars distalis of the pituitary gland of rats as well as other species has been studied under normal and various experimental conditions. The object of this work was to relate the different anterior pi- tuitary hormones to a specific cell type in the pars distalis. Schoenemann (1892) was the first to observe that the secretory gran- ules of the anterior pituitary cells either had a staining affinity for acid or basic dyes or did not stain. The cells were designated as chromophils and chromophobes and the chromophils were divided into acidophils and ba- sophils. A more definitive classification was made possible by application of the periodic acid-Schiff (PAS) reaction which stains gonadotropes and thyrotropes and aldehyde-fuchsin (AF) which also stains thyro- tropes. Acidophils have been separated into two cell types by using or- ange G and azocarmine. Also, autoradiography and immunofluorescence have helped elucidate some cell types at the light microscopic level. A summary of the current views on histochemistry of the pituitary gland is given in Table 1.1. Reviews of the many staining techniques used in determining the his- tology of the anterior pituitary gland have been presented by Landing (1954) and by Herlant (1964). The experimental evidence and its inter- pretation as to cell types has been reviewed by Severinghaus (1937, 1938, 1939), Pearse (1952), Desclin (1952), Hartley (1959), Ezrin (1963), McShan (1965), Holmes (1964), and Vanha-Perttula (1966). Recent general reviews include those by Kracht (1957), Purves (1961, 1966), Herlant (1964, 1965), McShan and Hartley (1965), and Costoff (1969). 1 5 n atio Al- AND THEIR PROPERTIES Method of CharacterizTetrachrome Acromegaly Tumors Dwarf mice Orange G Area of pituitary STH releasers Lactation Tumors Brick red Autograft to kidney Disease Blocking Agents Violet Adrenalectomy Cortisone Tumors Thyroxin Dark blue Thyroidectomy Thiourea Castration Estrogen Light blue Estrous cycle Blocking agents Castration Estrogen Estrous cycle Light blue Blocking agents cells Stem degranulated cells Follicle cells Cleft cells trachrome consists of PAS, Orange G, 0S Te PE s" e. Y c n T sti mi TABLE 1.1 NTERIOR PITUITARY CELL Staining characteri ACID PAS + Orange G + Carmine + + Purple + Red ody methods. ains; Orange G, azocar RAT A nt-antib acid st EWS OF AF + Red fluoresce ACID, VI RENT using Schiff; A SUMMARY OF CUR Hormone Cell type Somatotropin Acidophil Somatotrope Luteotropin Acidophil Luteotrope Corticotropin Acidophil Corticotrope Thyrotropin Basophil Thyrotrope Follicle-Basophil stimulating Peripheral hormone gonadotrope Luteinizing Basophil hormone Central gonadotrope Acidophilic No specific hormone Basophilic chromophobes "Many of these cells have been identified 6 AF, aldehyde fuchsin; PAS, periodic acid- cian blue, alizarine blue. Introduction 3 Although much knowledge of the cell types has come from the study of stained sections, the development of electron microscopic techniques is proving of equal or greater value in the study of pituitary morphology. Moreover, by means of electron microscopy the action of certain en- zymes can be studied and located at the intracellular level (electron mi- croscopic histochemistry). Other methods have made use of isotopes (high resolution autoradiography), intracellular antibodies coupled with peroxidase (immunoelectron microscopy), and the viewing of sections of cellular fragments after negative staining. Electron microscopic studies of rat pituitaries have been made by Farquhar and Rinehart (1954), Kuro- sumi and Oota (1968), Fawcett et al. (1969), and Siperstein and Miller (1970); of the mouse pituitary, by Barnes (1963); salamander, Cardell (1963) ; rabbit, Salazar (1963) ; hamster, Girod and Dubois (1965) ; and cow, Heath (1970). Extensive cytological and histological research has been undertaken on anterior pituitaries of many species. This histological work, correlated with physiological experiments, forms the basis for the generally accepted concept that specific cell types synthesize, store, and release each of the anterior pituitary hormones, and that the hormones are stored in or asso- ciated with granules. There is general agreement that six hormones are produced by the pars distalis of the adenohypophysis. These hormones are somatotropin (growth hormone, STH) ; luteotropin (mammotropin, prolactin, LTH) ; thyrotropin (thyroid stimulating hormone, TSH) ; folli- cle-stimulating hormone (FSH) ; luteinizing hormone (LH) in the female or interstitial cell-stimulating hormone (ICSH) in the male; and cortico- tropin (adrenocorticotropic hormone, ACTH). The pars intermedia produces melanocyte-stimulating hormone (MSH) and perhaps ACTH. Lipotropic hormone has also been associated with the adenohypophysis in some species. Cytoplasmic particulate fractions of the pituitary glands from several species of animals have been prepared during recent years, beginning in 1948 with the work of Catchpole (1948). The earliest isolation proce- dures for the rat were made by McShan and Meyer (1949). Their meth- ods involved differential centrifugation. More recently continuous and discontinuous gradient centrifugation, microfiltration, and chromato- graphic procedures have been employed to obtain more homogeneous fractions of granules. Electron microscopy is now routinely employed to determine the degree of homogeneity of isolated organelles. Granule frac- tionation studies coupled with biological assays have proven valuable in identifying the cell types in the rat pituitary, and for determination of the biological, chemical, and physical characteristics of the granules.
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