Ultrastructure of prothoracic glands during larval‐pupal development of the tobacco hornworm, Manduca sexta: A reappraisal

Academic Article


  • The structure of Manduca sexta prothoracic glands was investigated using a protocol that preserves membranes. During the last larval stadium, prothoracic gland cells increase in diameter, volume, protein content, and perhaps number, enhancing their capacity to produce ecdysteroids. The glands' strand‐of‐cells morphology, their in situ location, the presence of gap junctions between cells, and junctional foot‐like structures within cells support previous findings that prothoracicotropic hormone stimulates ecdysteroidogenesis via Ca ‐induced Ca release. A different method of tissue fixation from that previously used to investigate the ultrastructure of Manduca sexta prothoracic glands has revealed a significantly different ultrastructure. These new findings begin to define roles for endoplasmic reticulum and mitochondria in ecdysteroid synthesis and support the hypothesis that the glands secrete the steroid hormone via exocytosis. The structural dynamics of the glands are discussed in the context of the glands' function during Manduca sexta larvalpupal development. © 1993 Wiley‐Liss, Inc. Copyright © 1993 Wiley‐Liss, Inc. 2+ 2+
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Hanton WK; Watson RD; Bollenbacher WE
  • Start Page

  • 95
  • End Page

  • 112
  • Volume

  • 216
  • Issue

  • 1