1. THE PITUITARY GLAND
3
on fishes are still primarily concerned with special cytology. This implies
that there is, as yet, no complete general agreement about the functions
of the various types of cell distinguishable in the fish pituitary; although
perhaps with the greater technical standardizations that have come about
in recent years, especially the use of methods developed in mammalian
studies by Herlant (1956, 1960), and first applied to the fish pituitary by
Olivereau and Herlant ( 1954, 1960), the actual morphological and tinctorial characteristics of the teleostean adenohypophysial cell types would
now be agreed upon by most workers. However, there is still disagreement about the functions of these cell types since the experimental allocation of function to the cells has been attempted systematically in only
a few species. It follows that not all workers in this field would agree on
a generally applicable functional nomenclature of cell types. In this review, the nomenclature used is the one established partly on functional
and partly on tinctorial grounds following experimental studies in the
eel, Anguilh, and the molly, Poecilia (Olivereau, 1963b; Olivereau and
Ball, 1964). It is a mixed nomenclature, in Purves’ terms (1966), based
partly on similarities in staining properties of the secretory granules to
those in mammalian cells of demonstrated function but mainly (primarily) on the characteristic responses of the cells in fishes to experimental situations designed to alter the secretion rates of the different
adenohypophysial hormones. Logically, one is on equivocal ground in
applying this nomenclature to species in which such experimentation
has not been performed. But in the teleosts, which include the vast majority of fishes, the distribution of cell types within the adenohypophysis
is extremely regular so that to a far greater extent than in other vertebrate groups the topographical location of a cell type can support its
identification on tinctorial grounds. Nevertheless, it must be recognized
that the extension of Olivereau’s mixed nomenclature to all teleosts would
not yet be accepted by all workers on the fish pituitary, and the reader
new to this field should bear this in mind. It seems to us that the alternative, to perpetuate yet another purely numerical or Greek letter morphological system, would present further opportunities for the extension to
fishes of the nomenclatural confusions that are rife in pituitary studies on
higher vertebrates (see Herlant, 1964; Purves, 1966). We think that tinctorial and locational grounds alone are usually sufficiently certain criteria
for the extension of the Olivereau nomenclature from those fishes in which
it has an experimentally defined functional basis ( Anguillu, Poecilia, and
Mugi2 and for certain cell types a few other species) to the vast majority
of teleosts in which the desirable experimental backing is lacking. Unfortunately, there are almost no certain grounds for extending the system
to nonteleostean groups.
Frequent reference will be made to the staining properties of the cells.
3
on fishes are still primarily concerned with special cytology. This implies
that there is, as yet, no complete general agreement about the functions
of the various types of cell distinguishable in the fish pituitary; although
perhaps with the greater technical standardizations that have come about
in recent years, especially the use of methods developed in mammalian
studies by Herlant (1956, 1960), and first applied to the fish pituitary by
Olivereau and Herlant ( 1954, 1960), the actual morphological and tinctorial characteristics of the teleostean adenohypophysial cell types would
now be agreed upon by most workers. However, there is still disagreement about the functions of these cell types since the experimental allocation of function to the cells has been attempted systematically in only
a few species. It follows that not all workers in this field would agree on
a generally applicable functional nomenclature of cell types. In this review, the nomenclature used is the one established partly on functional
and partly on tinctorial grounds following experimental studies in the
eel, Anguilh, and the molly, Poecilia (Olivereau, 1963b; Olivereau and
Ball, 1964). It is a mixed nomenclature, in Purves’ terms (1966), based
partly on similarities in staining properties of the secretory granules to
those in mammalian cells of demonstrated function but mainly (primarily) on the characteristic responses of the cells in fishes to experimental situations designed to alter the secretion rates of the different
adenohypophysial hormones. Logically, one is on equivocal ground in
applying this nomenclature to species in which such experimentation
has not been performed. But in the teleosts, which include the vast majority of fishes, the distribution of cell types within the adenohypophysis
is extremely regular so that to a far greater extent than in other vertebrate groups the topographical location of a cell type can support its
identification on tinctorial grounds. Nevertheless, it must be recognized
that the extension of Olivereau’s mixed nomenclature to all teleosts would
not yet be accepted by all workers on the fish pituitary, and the reader
new to this field should bear this in mind. It seems to us that the alternative, to perpetuate yet another purely numerical or Greek letter morphological system, would present further opportunities for the extension to
fishes of the nomenclatural confusions that are rife in pituitary studies on
higher vertebrates (see Herlant, 1964; Purves, 1966). We think that tinctorial and locational grounds alone are usually sufficiently certain criteria
for the extension of the Olivereau nomenclature from those fishes in which
it has an experimentally defined functional basis ( Anguillu, Poecilia, and
Mugi2 and for certain cell types a few other species) to the vast majority
of teleosts in which the desirable experimental backing is lacking. Unfortunately, there are almost no certain grounds for extending the system
to nonteleostean groups.
Frequent reference will be made to the staining properties of the cells.