Abstract 1. 1. The epinephrine and norepinephrine content of plasma of Nembutal-anesthetized rats... more Abstract 1. 1. The epinephrine and norepinephrine content of plasma of Nembutal-anesthetized rats in various thyroid states was determined. One liter of plasma from normal rats had 6.2 μg. norepinephrine and 0.9 μg. epinephrine. One liter of plasma from thyroidectomized rats had 6.7 μg. norepinephrine and 2.1 μg. epinephrine. Plasma from thyroid-fed animals had 12.0 μg. norepinephrine and 4.0 μg. epinephrine per liter. 2. 2. A comparison of hepatic mitochondrial monoamine oxidase activity of rats in different thyroid states revealed that mitochondria from normal rats oxidized tyramine twice as fast as did those from rats fed thyroid substance. 3. 3. Monoamine oxidase activity declined steadily during thyroid feeding and was restored to normal levels after discontinuing the treatment. 4. 4. Evidence is presented that the decreased monoamine oxidase activity in the liver of thyroid-fed rats is not due to direct inhibition of the enzyme by thyroid hormone or other inhibitors in the tissue. 5. 5. The monoamine oxidase is distributed among the various cellular components in the same relative amounts in livers of thyroid-fed rats as in normal rats. 6. 6. Partial solubilization of monoamine oxidase resulted after sonation of acetone-dried hepatic mitochondria.
... Regular Article. Retinoid Signaling Is Required to Complete the Vertebrate Cardiac Left/Right... more ... Regular Article. Retinoid Signaling Is Required to Complete the Vertebrate Cardiac Left/Right Asymmetry Pathway *1. Maija H. Zile a , 1 , Igor Kostetskii a , Saying Yuan a , Ekaterina Kostetskaia a , Tara R. St. ... Virchows Arch. (Cell Pathol.) 50 (1985), pp. 135152. ...
We examined the effect of vitamin A nutritional status on cell division in various epithelial tis... more We examined the effect of vitamin A nutritional status on cell division in various epithelial tissues of the rat. Tissues were examined by histological methods, and DNA labeling was assessed by autoradiography. Mild vitamin A deficiency decreased the DNA labeling index in the trachea and the epidermis, while not altering the histological appearance of the tissue. In some tracheae, foci of hyperplasia were present. The histological appearance and the DNA labeling index of the cornea, jejunum and colon were not altered by mild vitamin A deficiency. We concluded that a diminished proliferation of epithelial cells is a manifestation of suboptimal vitamin A availability in that tissue.
The potential of all-trans-5,6-epoxyretinoic acid to promote growth in vitamin A-deficient rats w... more The potential of all-trans-5,6-epoxyretinoic acid to promote growth in vitamin A-deficient rats was evaluated over a 25-fold dose range using single daily intraperitoneal injections. 5,6-Epoxyretinoic acid was found to be 0.5% as active as all-trans-retinoic acid. The discrepancies between the present results and those obtained previously by other workers are discussed.
Cell division kinetics and the biochemical composition of the small intestine of normal and mildl... more Cell division kinetics and the biochemical composition of the small intestine of normal and mildly vitamin A-deficient rats have been examined. Thymidine labeling index, growth fraction and the content of DNA, RNA and protein in the jejunal mucosa were not significantly affected by vitamin A deficiency. On the other hand, the duration of the cell cycle of jejunal crypt cells was found to be lengthened by vitamin A deficiency and this increase in generation time was due mainly to a lengthening of the DNA synthesis phase. Furthermore, the labeling pattern of the newly divided crypt cells of the vitamin A-deficient rats was strikingly different from that of the vitamin A-supplemented rats, suggesting an impaired migration of cells out of the crypts. These findings suggest that vitamin A may play a role in the regulation of cell division in the small intestine of the rat.
Vitamin A deficiency had no effect on serum calcium levels but decreased markedly the urinary exc... more Vitamin A deficiency had no effect on serum calcium levels but decreased markedly the urinary excretion of calcium. Creatinine clearance and urinary protein levels were not altered by vitamin A deficiency. The decrease in urinary calcium occurred very early in the depletion period and was rapidly re stored to normal by retinol administration. It is suggested that the urinary cal
Proceedings of the National Academy of Sciences, 1980
Several metabolites detected in the bile of rats given radioactive retinoic acid were separated b... more Several metabolites detected in the bile of rats given radioactive retinoic acid were separated by liquid/gel partition chromatography and purified by high-pressure liquid chromatography. One of these metabolites was found to be sensitive to beta-D-glucuronidase, yielding both 13-cis- and all-trans-retinoic acid. It had the characteristic ultraviolet absorption spectrum of retinoic acid esters. Trimethylsilyl ether and acetyl derivatives of the methylated metabolite were prepared and examined by mass spectrometry. The resulting mass spectra established the structure to be retinoyl beta-glucuronide. Retinoyl glucuronide was rapidly excreted into the bile: the excretion was complete by 12 hr after the administration of retinoic acid. At this time the metabolite represented 12% of bile radioactivity (10% of dose). These observations confirm the existence of retinoyl glucuronide but demonstrate that it represents only one of several retinoic acid metabolites in bile.
Abstract 1. 1. The epinephrine and norepinephrine content of plasma of Nembutal-anesthetized rats... more Abstract 1. 1. The epinephrine and norepinephrine content of plasma of Nembutal-anesthetized rats in various thyroid states was determined. One liter of plasma from normal rats had 6.2 μg. norepinephrine and 0.9 μg. epinephrine. One liter of plasma from thyroidectomized rats had 6.7 μg. norepinephrine and 2.1 μg. epinephrine. Plasma from thyroid-fed animals had 12.0 μg. norepinephrine and 4.0 μg. epinephrine per liter. 2. 2. A comparison of hepatic mitochondrial monoamine oxidase activity of rats in different thyroid states revealed that mitochondria from normal rats oxidized tyramine twice as fast as did those from rats fed thyroid substance. 3. 3. Monoamine oxidase activity declined steadily during thyroid feeding and was restored to normal levels after discontinuing the treatment. 4. 4. Evidence is presented that the decreased monoamine oxidase activity in the liver of thyroid-fed rats is not due to direct inhibition of the enzyme by thyroid hormone or other inhibitors in the tissue. 5. 5. The monoamine oxidase is distributed among the various cellular components in the same relative amounts in livers of thyroid-fed rats as in normal rats. 6. 6. Partial solubilization of monoamine oxidase resulted after sonation of acetone-dried hepatic mitochondria.
... Regular Article. Retinoid Signaling Is Required to Complete the Vertebrate Cardiac Left/Right... more ... Regular Article. Retinoid Signaling Is Required to Complete the Vertebrate Cardiac Left/Right Asymmetry Pathway *1. Maija H. Zile a , 1 , Igor Kostetskii a , Saying Yuan a , Ekaterina Kostetskaia a , Tara R. St. ... Virchows Arch. (Cell Pathol.) 50 (1985), pp. 135152. ...
We examined the effect of vitamin A nutritional status on cell division in various epithelial tis... more We examined the effect of vitamin A nutritional status on cell division in various epithelial tissues of the rat. Tissues were examined by histological methods, and DNA labeling was assessed by autoradiography. Mild vitamin A deficiency decreased the DNA labeling index in the trachea and the epidermis, while not altering the histological appearance of the tissue. In some tracheae, foci of hyperplasia were present. The histological appearance and the DNA labeling index of the cornea, jejunum and colon were not altered by mild vitamin A deficiency. We concluded that a diminished proliferation of epithelial cells is a manifestation of suboptimal vitamin A availability in that tissue.
The potential of all-trans-5,6-epoxyretinoic acid to promote growth in vitamin A-deficient rats w... more The potential of all-trans-5,6-epoxyretinoic acid to promote growth in vitamin A-deficient rats was evaluated over a 25-fold dose range using single daily intraperitoneal injections. 5,6-Epoxyretinoic acid was found to be 0.5% as active as all-trans-retinoic acid. The discrepancies between the present results and those obtained previously by other workers are discussed.
Cell division kinetics and the biochemical composition of the small intestine of normal and mildl... more Cell division kinetics and the biochemical composition of the small intestine of normal and mildly vitamin A-deficient rats have been examined. Thymidine labeling index, growth fraction and the content of DNA, RNA and protein in the jejunal mucosa were not significantly affected by vitamin A deficiency. On the other hand, the duration of the cell cycle of jejunal crypt cells was found to be lengthened by vitamin A deficiency and this increase in generation time was due mainly to a lengthening of the DNA synthesis phase. Furthermore, the labeling pattern of the newly divided crypt cells of the vitamin A-deficient rats was strikingly different from that of the vitamin A-supplemented rats, suggesting an impaired migration of cells out of the crypts. These findings suggest that vitamin A may play a role in the regulation of cell division in the small intestine of the rat.
Vitamin A deficiency had no effect on serum calcium levels but decreased markedly the urinary exc... more Vitamin A deficiency had no effect on serum calcium levels but decreased markedly the urinary excretion of calcium. Creatinine clearance and urinary protein levels were not altered by vitamin A deficiency. The decrease in urinary calcium occurred very early in the depletion period and was rapidly re stored to normal by retinol administration. It is suggested that the urinary cal
Proceedings of the National Academy of Sciences, 1980
Several metabolites detected in the bile of rats given radioactive retinoic acid were separated b... more Several metabolites detected in the bile of rats given radioactive retinoic acid were separated by liquid/gel partition chromatography and purified by high-pressure liquid chromatography. One of these metabolites was found to be sensitive to beta-D-glucuronidase, yielding both 13-cis- and all-trans-retinoic acid. It had the characteristic ultraviolet absorption spectrum of retinoic acid esters. Trimethylsilyl ether and acetyl derivatives of the methylated metabolite were prepared and examined by mass spectrometry. The resulting mass spectra established the structure to be retinoyl beta-glucuronide. Retinoyl glucuronide was rapidly excreted into the bile: the excretion was complete by 12 hr after the administration of retinoic acid. At this time the metabolite represented 12% of bile radioactivity (10% of dose). These observations confirm the existence of retinoyl glucuronide but demonstrate that it represents only one of several retinoic acid metabolites in bile.
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