Cytochemical analysis of intracellular distribution in the anterior pituitary of the rat

In an attempt to assign morphologic identities to previously distinguished functional calcium compartments in the anterior pituitary of the rat, we employed the potassium pyroantimonate technique for cation localization. Tissues were incubated for 1 h at 37 degrees C in control medium; with 10 mM th...

Full description

Saved in:
Bibliographic Details
Published in:Cell and tissue research 1981, Vol.220 (1), p.191-200
Main Authors: Leuschen, M P, Moriarty, C M, Sampson, H W, Piscopo, I
Format: Article
Language:English
Subjects:
Animals
Calcium - analysis
Cell Membrane - analysis
Cytoplasmic Granules - analysis
Endoplasmic Reticulum - analysis
Heterochromatin - analysis
Male
Mitochondria - analysis
Pituitary Gland, Anterior - analysis
Pituitary Gland, Anterior - ultrastructure
Potassium - pharmacology
Rats
Theophylline - pharmacology
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In an attempt to assign morphologic identities to previously distinguished functional calcium compartments in the anterior pituitary of the rat, we employed the potassium pyroantimonate technique for cation localization. Tissues were incubated for 1 h at 37 degrees C in control medium; with 10 mM theophylline; or with depolarizing amounts of potassium. Precipitate was quantified on photomicrographs of tissue prepared for electron microscopy with a Talos Systems Digitizer. The nature of the electron dense precipitate was dependent on the experimental state of the tissue. Treatment with 5 mM EGTA abolished the dense precipitate. Electron microprobe analysis also confirmed that calcium was the predominant cation in the observed precipitate. The most significant changes in precipitate deposition occurred along the plasma membrane, the limiting membrane of secretory granules and within mitochondria. Dense precipitate was present along the plasma membrane only in cells treated with potassium. Control tissue exhibited higher levels of precipitate associated with the limiting membrane of secretory granules than either theophylline-treated or potassium-treated tissue. Mitochondria contained more precipitate in potassium-treated tissue than in controls, the mitochondria of theophylline-treated tissue contained intermediate levels of precipitate. Addition of either theophylline or depolarizing amounts of potassium has been associated with hormone secretion in anterior pituitary tissue of normal rats. Kinetic studies in our laboratory indicate that intracellular calcium shifts occur. The pyroantimonate technique is useful in verifying morphologically the calcium compartments involved in shifts in intracellular calcium.
ISSN:0302-766X