Abstract
A histological and histometrical estimation was made on the adenohypophyseal cells of bilaterally adrenalectomized adult rats, which were sacrificed at various time-intervals from 6 hours to 32 days. The thyroid weight decreased, then rose again, being stabilized below the normal level after 3 days. The pituitary weight dropped slightly at 3 days, but soon returned to normal. The change in cell-height of the central follicles in thyroids was variable and exhibited no definite tendency. The height of epithelium of the ventral prostate tended to decrease gradually in a straight line. The cell-count resulted in a conclusion that the ranges of acidophils and chromophobes have an early and late peak. A slight decreasing shift was found in gonadotrophs. The curve of thyrotrophs represented a decreasing shift following an initial temporary rise. The population of intermediate cells between the chromophobes and chromophils was so intricate that its significance was hard to determine. The curve, including two peaks, of pituitary ACTH content in rats after adrenalectomy (Gemzell et al., 1951 and Fortier, 1959) was compatible with the population curve of chromophobes and acidophils, but inconsistent with that of the other cell elements. An early degranulation and subsequent accumulation of the α-granules in acidophils might be signs of discharge and secondary storage of the hormonal precursor in acidophils. It was suggested that the axis of the cellular transmigration from a chromophobe into an acidophil is likely to be concerned with ACTH secretion, because the population of chromophobes usually precedes that of the acidophils.
