Three-dimensional and quantitative observation of the hypertrophy of rat corticotrophs following adrenalectomy.

The three-dimensional form of corticotrophs in the anterior pituitary gland of rats was studied by reconstruction from serial semi-thin sections both in control rats and rats one week after adrenalectomy. The corticotrophs have large depressions and cup-shaped cavities on their surface, and these features became more conspicuous after adrenalectomy. The hypertrophy of corticotrophs in adrenalectomized rats was quantified by measuring the area and perimeter of all serially sectioned profiles. The volume of the whole cell increased from 1129 +/- 114 microns3 to 2902 +/- 201 microns3 (P less than 0.01) after adrenalectomy, while the surface area of the cells increased from 690 +/- 45 microns2 to 1431 +/- 116 microns2 (P less than 0.01). The volume of the nucleus increased from 87 +/- 11 microns3 to 172 +/- 14 microns3 (P less than 0.05). Though the complexity of the form of corticotrophs seems to be increased after adrenalectomy, the ratios (adrenalectomized/control) of cell volume and surface area were 2.57 and 2.07, respectively; this indicates that the increase of the cell volume was greater than that of the surface area.