[Hormone-dependent distribution of enzymes in tissues. 8. The phosphomonoesterases of th rat kidney after extripation of various endocrine glands]

Histochemistry and Cell Biology-a glance into the past and a look ahead

At the occasion of the 65th anniversary of Histochemistry and Cell Biology, we browse through its first ten years of publication and highlight a selection of papers from the early days of enzyme, protein, and carbohydrate histochemistry. In addition, we narrate recent progress to identify, quantify, and precisely determine the tissue localization of proteins and lipids, and small molecules by the combination of spectroscopic techniques and histology.

Histochemical, autoradiographic and electron microscopic investigations of the renal proximal tubule of male and female rats after castration

After castration of 90-day-old male and female rats, changes appear in the renal proximal tubule. A distinction can be made between early changes (up to 10th postoperative day) and later changes (20th-30th postoperative day). Between the 3rd and 5th day after castration the kidney of the females shows an increase in free estrogen receptors (biochemical studies) which are localized in the pars contorta of the proximal tubule (autoradiographic studies), while the male kidney shows a marked increase in urinary protein excretion up to the 10th day after castration. Proximal tubule changes detectable histochemically and electron microscopically do not appear until day 20 or 30 after castration. The results of castration are similar in segments S1 and S2. By days 20 and 30 after castration there is a decrease in the activity of lysosomal enzymes (acid phosphatase, acid beta-galactosidase). Electron microscopy shows a conspicuous decrease in the number of giant lysosomes (mainly in females) and apical vacuoles (mainly in males). A marked increase in the number of lysosomes is found in the S3 segment; females always have more lysosomes than males. The number of peroxisomes is also greatly increased; they appear circular in the females but can assume bizarre shapes in the males. Lipid droplets appear in the basal region of the tubule cell of segments S2 and S3 in the males. The sex differences are preserved in all segments even after castration and become even more pronounced in the S3 segment.

The effect of sex hormones on the proximal tubules in the rat kidney

The three segments (S1, S2, S3) of the proximal tubule of the rat kidney were investigated, with special reference to lysosomes, after castration, estradiol application, and at the end of pregnancy. Especially in S1 and S2 castration induces an increase of cellular autophagy. The nuclei become smaller; endoplasmic reticulum (ER), ribosomes, and Golgi apparatus are reduced; catabolism predominates. In S1 more giant lysosomes occur; the total number of lysosomes increases whereas acid phosphatase activity decreases at the same time. Sex differences which exist in untreated animals disappear. Substitution with estradiol causes an activation of the proximal tubule cells: Heterophagy predominates, and cellular autophagy is reduced. Nuclear size is unchanged; ER, ribosomes and Golgi apparatus show a clear increase. Giant lysosomes are absent in S1. On the whole lysosomes are larger, but less numerous than after castration. Acid phosphatase is highly active. All changes are most evident in S3. At the end of pregnancy the proximal tubule cells are "stressed" considerably: Pinocytotic activity increases, and large numbers of cell organelles and many lipid vacuoles can be observed. The basal lamina in S1 and S2 becomes thicker. Lysosomes enlarge and increase in number in all segments; giant lysosomes are absent in S1; acid phosphatase is extremely high. The results indicate that sex hormones directly influence the regulation of the proximal tubule cell; moreover, they are indirectly important for the functioning of the kidney via changes in the whole organism.