32 



SOURCES OF KINETIC AND METABOLIC HORMONES 



Storage of the neurosecretion from the brain in the corpora 

 cardiaca has been conclusively shown in the cockroach, Leuco- 

 phaea, where the system is paired (B. Scharrer, 1952). Unilateral 

 section of the axons from the median neurosecretory cells results 



ax.b 



(a) Corpus cardiacum 



(b) Corpus allatum 



Fig. 2-9. Sections of parts of {a) the corpus cardiacum of a beetle, 

 Hydrous piceus (after de Lerma, 1956), and (b) the corpus allatum 

 of a grasshopper, Melanoplus differ entialis (after Mendes, 1948). 

 Axons (ax.b) from neurosecretory cells in the brain carry granules ; 

 some end in swellings (s.ax), like Herring bodies, and release masses 

 of neurosecretion (ns) in the corpus cardiacum. Cells in different 

 phases of secretion (sc and sc') release masses of granules (mg) that 

 stain with phloxin, and may be the intrinsic secretion of the organ. 

 Tracheoles (t) and non-secreting nerve cells (en) also occur. Other 

 axons (ax.c) pass to the cells of the corpus allatum, where their 

 granules disappear. It has undifferentiated cells (uc), secreting 

 (sc") and giant secreting cells with polyploid nuclei (gsc) ; acidophil 

 granules pass with some fluid into intracellular vacuoles and are 

 then extruded (v). 



in the depletion of all stainable secretion from the corpus cardia- 

 cum of that side. At the same time, increased quantities of the 

 secretion appear in the axons proximal to the cut (Fig. 3-2). The 

 corpora cardiaca are nearly always fused with the dorsal blood 

 vessel or aorta, into which they presumably pass the stored secre- 

 tion as required (Hanstrom, 1940). 



