Autoradiographic Demonstration of Thyroid Hormone Binding to Intact Liver Cells in Vivo.

Smith, Dale M.; Hitchcock, Karen R.

doi:10.1210/endo-111-3-1015

Cited by 5 publications

(3 citation statements)

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“…This suggests that the differences observed were due to intrinsic differences between cell populations. Quantitative autoradiography has recently been applied successfully to the in vivo J. E. HEWITT AND M. W. SMITH study of T3 binding to liver and lung (Smith & Hitchcock, 1982 and there have also been binding studies for insulin (Bergeron, Rachubinski, Searle, Borts, Sikstrom & Posner, 1980) and calcitriol (Zile, Bunge, Barsness, Yamada, Schnoes & DeLuca, 1978) in the intestine. Present work shows that it is possible to use this technique to identify the cellular distribution of T3 in enterocytes.…”

Section: Discussionmentioning

confidence: 99%

Thyroid hormone effects on lactase expression by rat enterocytes.

Hewitt¹,

Smith²

1986

The Journal of Physiology

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SUMMARY1. Thyroxine (T4) and triiodothyronine (T3) injected into adult rats causes first an increase and then a decrease in lactase activity measured subsequently in intestinal homogenates of rat jejunum. These changes are not associated with any alteration in intestinal structure or enterocyte migration rate.2. Quantitative cytochemistry shows T4 stimulation and inhibition of lactase activity to take place in upper villus and crypt cells respectively (0-and C-enterocytes). T3 injected into thyroidectomized rats produces identical stimulatory effects on lactase development to T4 injected into control animals.3. Radioactive T3 is distributed in all cell types following intraperitoneal injection into thyroidectomized rats. Highest amounts of recovered T3 are found in C-rather than 0-enterocytes. Quantitative autoradiography shows intracellular T3 to be located in nuclear and cytoplasmic compartments following intraperitoneal injection. Simultaneous injection of non-radioactive hormone displaces 50-750o of radioactive T3.4. These results are discussed in relation to what is already known concerning the ability of thyroid hormones to affect intestinal development. The future need to study the physiological effects of T3 at the cellular level in the intestine is also emphasized.

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Section: Discussionmentioning

confidence: 99%

Thyroid hormone effects on lactase expression by rat enterocytes.

Hewitt¹,

Smith²

1986

The Journal of Physiology

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“…At the end of the incubation, the preparation were repetitively washed for 10 min in cold PBS pH 7.4. After a 4% glutaraldehyde fixation for 30 min, [LZ51]-labeled T, retained in the specimens was covalently crosslinked to binding sites (19,20). Finally the preparations were rinsed with distilled water, then dried.…”

Section: Binding Proceduresmentioning

confidence: 99%

“…The concept that the effects of thyroid hormones are mediated by nuclear receptors emerged when high affinity binding sites for 3,5,5' triiodothyronine ( T,) were found in nuclear fractions of various target tissues (6)(7)(8)(9)(10) including neurons and glial cells from rat brain ( 1 1-15). Yet several radioautographic attempts failed to visualize clearly T, receptors at the cellular level in the nervous system (16,17) or liver (18)(19)(20) after in vivo injection of ['311]-or ['251]-labeled T,. A decisive stepforward was achieved by the production of a monoclonal antibody raised to the nuclear T, receptor of the rat liver (2 1).…”

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Nuclear and Cytoplasmic Triiodothyronine‐Binding Sites in Primary Sensory Neurons and Schwann Cells: Radioautographic Study During Development

Walter

1995

J Neuroendocrinology

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The effects of the thyroid hormones on target cells are mediated through nuclear T3 receptors. In the peripheral nervous system, nuclear T3 receptors were previously detected with the monoclonal antibody 2B3 mAb in all the primary sensory neurons throughout neuronal life and in peripheral glia at the perinatal period only (Eur. J. Neurosci. 5, 319, 1993). To determine whether these nuclear T3 receptors correspond to functional ones able to bind T3, cryostat sections and in vitro cell cultures of dorsal root ganglion (DRG) or sciatic nerve were incubated with 0.1 nM [125I]-labeled T3, either alone to visualize the total T3-binding sites or added with a 10(3) fold excess of unlabeled T3 to estimate the part due to the non-specific T3-binding. After glutaraldehyde fixation, radioautography showed that the specific T3-binding sites were largely prevalent. The T3-binding capacity of peripheral glia in DRG and sciatic nerve was restricted to the perinatal period in vivo and to Schwann cells cultured in vitro. In all the primary sensory neurons, specific T3-binding sites were disclosed in foetal as well as adult rats. The detection of the T3-binding sites in the nucleus indicated that the nuclear T3 receptors are functional. Moreover the concomitant presence of both T3-binding sites and T3 receptors alpha isoforms in the perikaryon of DRG neurons infers that: 1) [125I]-labeled T3 can be retained on the T3-binding 'E' domain of nascent alpha 1 isoform molecules newly-synthesized on the perikaryal ribosomes; 2) the alpha isoforms translocated to the nucleus are modified by posttranslational changes and finally recognized by 2B3 mAb as nuclear T3 receptor. In conclusion, the radioautographic visualization of the T3-binding sites in peripheral neurons and glia confirms that the nuclear T3 receptors are functional and contributes to clarify the discordant intracellular localization provided by the immunocytochemical detection of nuclear T3 receptors and T3 receptor alpha isoforms.

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Mitochondrial binding of triiodothyronine (T3)

et al. 1984

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To assess the distribution of the thyroid hormone triiodothyronine (T3) within intact living cells, freshly prepared dispersed rat hepatocytes were incubated with [125I]-T3 for periods of 5 min and 30 min. Light- and electron-microscopic (EM) radioautography was carried out to determine the distribution of grains over the isolated cells. Both procedures showed the grains distributed almost entirely over the cytoplasmic matrix rather than the nucleus. Grain counts under the EM were compared with expectation based on established quantitative methods. Only the mitochondria showed obvious and statistically significant grain counts, whereas the nucleus failed to accumulate grains in excess of expectations by chance alone based on area. The findings support the existence of mitochondrial binding of T3, presumably a prerequisite for its action in direct stimulation of the mitochondria.

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Autoradiographic Demonstration of Thyroid Hormone Binding to Intact Liver Cells in Vivo.

Cited by 5 publications

References 0 publications

Thyroid hormone effects on lactase expression by rat enterocytes.

Thyroid hormone effects on lactase expression by rat enterocytes.

Nuclear and Cytoplasmic Triiodothyronine‐Binding Sites in Primary Sensory Neurons and Schwann Cells: Radioautographic Study During Development

Mitochondrial binding of triiodothyronine (T3)

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