Premium
A CONTRIBUTION TO THE COMPARATIVE PHYSIOLOGY OF THE PITUITARY BODY
Author(s) -
Herring P. T.
Publication year - 1908
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1908.sp000018
Subject(s) - pars intermedia , lobe , posterior pituitary , pituitary gland , anatomy , biology , secretion , lateral ventricles , infundibulum , pathology , epithelium , endocrinology , medicine , hormone
In mammamals, birds, and bony fishes the pituitary body consists of two lobes, an anterior or epithelial which has the structure of a gland secreting into blood‐vessels, and a posterior composed of nervous tissue more or less surrounded and invaded by epithelial cells of the pars intermedia. The posterior lobe may also furniish secretion into blood‐vessels, but its arrangement and histological features suggest a gland which pours its products into the infundibulum, and so into the ventricles of the brain. It may, therefore, be regarded, in part at least, as a special brain gland. Extracts of the anterior lobe have no immediate physiological action when injected into the blood‐vessels. Extracts of the posterior lobe of birds and bony fishes have an action similar to extracts of the mammalian posterior lobe, bringing about a rise of blood‐pressure, expansion of the kidney, and an increase in the secretion of urine. The tissue in which the active principles giving this result are found, contains, when examined histologically, bodies of a colloid nature such as have already been described in mammals in a previous paper. Whether this colloid contains the above‐mentioned active principles or not, is undecided; it may possibly be the expression of some other function. The close relationship which exists between pars nervosa and pars intermedia of the posterior lobe renders it probable that the active principles, and especially the colloid bodies, are furnished by the epithelial cells, but it is possible that the ependyma cells have also a secretory function. The pituitary body of elasmobranchs differs widely in structure from that of the other classes considered. It is a gland which apparently secretes directly into the blood‐vessels, but it contains none of the deeply staining (chromophil) cells which are characteristic of the anterior lobe of mammals and teleosts. Its posterior lobe is absent or merely rudimentary. Extracts of the pituitary body of elasmobranchs have no immediate physiological activity. The saccus vasculosus secretes its products into the ventricles of the brain. Its extracts are inactive, and it is probably an auxiliary to the choroid plexus, aiding in the production of the large amount of cerebrospinal fluid which is found in fishes. I have to thank Mr Richard Muir for the care with which he has executed the accompanying illustrations. The expenses incurred have been assisted by a grant from the Carnegie fund for research‐work.