10
J. N. BALL AND BRIDGET I. BAKER
1. PROLACTIN CELLS (7 CELLS, ERYTHF~OSINOPHILIC CELLS,
OR PARALACTIN CELLS)
The prolactin cells lie mainly in the rostral region of the gland, where
they form a compact mass that is the main defining character of the
rostral pars distalis. In some species, perhaps in most, the prolactin cells
extend ventrally and laterally for a greater or lesser distance around the
proximal pars distalis, in winglike projections. Their specific secretory
granules (7 granules) stain red with the erythrosin in Aliz B tetrachrome
and the Cleveland Wolfe trichrome, and with the azocarmine or acid
fuchsin in other methods such as Azan, Mallory, and Masson (Figs. 2, 3,
and 4), but they are negative to PAS, Alcian blue, and aldehyde fuchsin.
Fig. 2. PoeciZiu hipinnu. Sagittal section through pituitary of a female fish, anterior to the right. The mass of prolactin cells (bright red) together with the bands
of colorless ACTH cells projecting into the neurohypophysis posteriorly form the
rostral pars distalis. In the proximal pars distalis, note the ventral mass of blue
gonadotrops and the dorsally projecting fingers of orange growth hormone cells, mixed
with a few blue TSH cells. The pars intermedia is small in cyprinodonts and forms a
thin ventral rim to the posterior neurohypophysis, which contains large Herring
bodies (neurosecretory material). Azan.
Fig. 3. PoeciZia latipinnu. Junction of rostral and proximal pars distalis. Note the
tinctorial distinction between the dull red prolactin cells above and the yellow growth
hormone cells below. The prominent mass of blue cells is an intrusive islet of pars
intermedia PAS + ve cells (Section 11, B, 6); below this islet are some gray ACTH
cells with characteristic elongated nuclei. Aliz B.
Fig. 4. AnguiZla unguilla. Junction of rostral and proximal pars distalis. Bright red
prolactin cells in rostral zone, contrasting with yellow growth hormone cells in proximal zone. A single blue TSH cell is visible. Aliz B.
Fig. 5. Poecilia latipinnu. Part of proximal pars distalis of a pregnant female, in
which vitellogenesis was arrested. Orange growth hormone cells mixed with bright
blue TSH cells. Below (ventrally) are inactive gonadotrops. Azan.
Fig. 6. Poeciliu latipinnu. Part of proximal pars distalis of a female with a maturing ovary, during rapid vitellogenesis. Above, orange growth hormone cells and blue
TSH cells, with neurohypophysial processes penetrating between the groups of cells.
Below, highly active gonadotrops (contrast Fig. 5 ) . Note that because of their R
granules the gonadotrops stain more deeply than the TSH cells with a purple tinge
(Section 11, B, 4). Azan.
Fig. 7. Sulmo guirdneri. Section of half a trout pituitary maintained in uitro for
6 days without thyroxine. The TSH cells (close to the connective tissue) are largely
degranulated but some retain a sparse blue granulation. Other cells present, away
from the connective tissue, are degranulated a cells. Aliz B.
Fig. 8. Salmo guirdneri. Section of the other half of the pituitary shown in Fig.
7, maintained in uitro for 6 days with 1 pg/ml synthetic thyroxine added to the
medium. Note that thyroxine induces retention of the blue granulation in the TSH
cells. Aliz B.
Fig. 9. Anguilla anguillu, pars intermedia, stained with PbH-PAS, to show the
two cell types, PAS + ve (pink) and PbH + ve ( gray or black).
J. N. BALL AND BRIDGET I. BAKER
1. PROLACTIN CELLS (7 CELLS, ERYTHF~OSINOPHILIC CELLS,
OR PARALACTIN CELLS)
The prolactin cells lie mainly in the rostral region of the gland, where
they form a compact mass that is the main defining character of the
rostral pars distalis. In some species, perhaps in most, the prolactin cells
extend ventrally and laterally for a greater or lesser distance around the
proximal pars distalis, in winglike projections. Their specific secretory
granules (7 granules) stain red with the erythrosin in Aliz B tetrachrome
and the Cleveland Wolfe trichrome, and with the azocarmine or acid
fuchsin in other methods such as Azan, Mallory, and Masson (Figs. 2, 3,
and 4), but they are negative to PAS, Alcian blue, and aldehyde fuchsin.
Fig. 2. PoeciZiu hipinnu. Sagittal section through pituitary of a female fish, anterior to the right. The mass of prolactin cells (bright red) together with the bands
of colorless ACTH cells projecting into the neurohypophysis posteriorly form the
rostral pars distalis. In the proximal pars distalis, note the ventral mass of blue
gonadotrops and the dorsally projecting fingers of orange growth hormone cells, mixed
with a few blue TSH cells. The pars intermedia is small in cyprinodonts and forms a
thin ventral rim to the posterior neurohypophysis, which contains large Herring
bodies (neurosecretory material). Azan.
Fig. 3. PoeciZia latipinnu. Junction of rostral and proximal pars distalis. Note the
tinctorial distinction between the dull red prolactin cells above and the yellow growth
hormone cells below. The prominent mass of blue cells is an intrusive islet of pars
intermedia PAS + ve cells (Section 11, B, 6); below this islet are some gray ACTH
cells with characteristic elongated nuclei. Aliz B.
Fig. 4. AnguiZla unguilla. Junction of rostral and proximal pars distalis. Bright red
prolactin cells in rostral zone, contrasting with yellow growth hormone cells in proximal zone. A single blue TSH cell is visible. Aliz B.
Fig. 5. Poecilia latipinnu. Part of proximal pars distalis of a pregnant female, in
which vitellogenesis was arrested. Orange growth hormone cells mixed with bright
blue TSH cells. Below (ventrally) are inactive gonadotrops. Azan.
Fig. 6. Poeciliu latipinnu. Part of proximal pars distalis of a female with a maturing ovary, during rapid vitellogenesis. Above, orange growth hormone cells and blue
TSH cells, with neurohypophysial processes penetrating between the groups of cells.
Below, highly active gonadotrops (contrast Fig. 5 ) . Note that because of their R
granules the gonadotrops stain more deeply than the TSH cells with a purple tinge
(Section 11, B, 4). Azan.
Fig. 7. Sulmo guirdneri. Section of half a trout pituitary maintained in uitro for
6 days without thyroxine. The TSH cells (close to the connective tissue) are largely
degranulated but some retain a sparse blue granulation. Other cells present, away
from the connective tissue, are degranulated a cells. Aliz B.
Fig. 8. Salmo guirdneri. Section of the other half of the pituitary shown in Fig.
7, maintained in uitro for 6 days with 1 pg/ml synthetic thyroxine added to the
medium. Note that thyroxine induces retention of the blue granulation in the TSH
cells. Aliz B.
Fig. 9. Anguilla anguillu, pars intermedia, stained with PbH-PAS, to show the
two cell types, PAS + ve (pink) and PbH + ve ( gray or black).