Page 182 - Veterinary Histology of Domestic Mammals and Birds, 5th Edition

164 Veterinary Histology of Domestic Mammals and Birds

In both cell groups, protein hormones are synthesised in the Acidophilic cells (endocrinocytus acidophilicus) contain
VetBooks.ir rough endoplasmic reticulum, glycosylated in the Golgi appa- secretory granules that stain with eosin, orange G or azo-
ratus and condensed and stored in membrane-bound secretory carmine. They comprise two cell populations:
granules (endocrine granules). Once released by exocytosis,
the contents of the granules pass through the fenestrated · somatotropes (STH or GH cells) and
endothelium of the sinusoids to enter the bloodstream. · lactotropes (luteotropic cells).
The number of chromophobic and different chromo-
philic cell types in the adenohypophysis varies considerably The large, densely packed granules (diameter 300–350 nm)
with species, age and sex. Generally, the highest proportion of the somatotrope (STH cell, GH cell, endocrinocytus
are chromophobes (50%), followed by acidophilic (40%) somatotropicus) contain somatotropic hormone (soma-
and basophilic (10%) cells. totropin, STH; growth hormone, GH). Growth hormone

9.3 Adenohypophysis (ox). With the light microscope, chromophobic cells of the adenohypophysis are not seen
to contain granules. In Azan-stained sections, the cytoplasm therefore appears pale and the nucleus stains red.
Chromophobes are considered stem cells for other endocrine cells of the adenohypophysis, or as cells that are
in an inactive phase following degranulation. Azan stain (x300).

9.4 Adenohypophysis (ox). With the light microscope, chromophilic cells are distinguished by the presence of
acidophilic or basophilic granules. Acidophils are somatotropes and lactotropes while basophils are gonado-
tropes, thyrotropes or corticotropes. Azan stain (x480).

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