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K Sterling

Publications and source records attributed to K Sterling.

12 recordsLinked to original sources
PubMed1991

Thyroid hormone action: identification of the mitochondrial thyroid hormone receptor as adenine nucleotide translocase.

A preliminary report from our laboratory suggested that the thyroid hormone triiodothyronine (T3) is bound with an association constant (Ka) approximating 2 x 10(11) M-1 by adenine nucleotide translocase (AdNT) purified from beef heart mitochondria. We now report that [125I]T3 is capable of photoaffinity labeling not only purified AdNT but also the carrier in intact beef heart mitochondria. Photoaffinity labeling in intact mitochondria was appreciably greater than that observed with purified AdNT. The covalently labeled AdNT was identified by 2-dimensional electrophoresis with pI of 10 on electrofocusing and M(r) of 31,000 on SDS gel. Identification of the covalently labeled protein as authentic AdNT was substantiated by its interaction with a specific monoclonal antibody preparation.

Animals↗
PubMed1978

Mitochondrial thyroid hormone receptor: localization and physiological significance.

Binding studies of thyroid hormone to submitochondrial fractions from rat liver suggest that the component responsible for high-affinity, low-capacity (saturable) binding of hormones arises from the inner mitochondrial membrane. The partially purified component, approximately 150,000 daltons, appears to be half protein and half lipid, largely phospholipids, tentatively identified as lecithin, phosphatidyl ethanolamine, and cardiolipin. A similar hormone-binding macromolecule was found in mitochondria from rabbit kidney, from human liver and kidney, and from rat kidney, myocardium, skeletal muscle, intestinal mucosa, whole small intestine, adipose tissue, and lung. It was absent from mitochondria of adult rat brain, spleen, and testis, organs calorigenically unresponsive to thyroid hormones injected in vivo, but was present in mitochondria from brains of rats 12 days old and younger. The organ distribution of the hormone-binding protein and its presence in neonatal brain mitochondria supports the biological relevance of the mitochondrial component as a thyroid hormone receptor.

Animals↗
PubMed1978

Partial purification of thyroid hormone receptor from mitochondrial inner membrane: evidence for a physiologic role.

Recently we described a protein component, from the inner mitochondrial membrane, which binds thyroid hormone with high affinity, low capacity (saturable) characteristics. This partially purified rat liver mitochondrial membrane component appears to be a 150,000 daltons lipoprotein complex. Phospholipids, tentatively identified as lecithin, phosphatidyl ethanoamine, and cardiolipin, appear to constitute 50% of this complex. A similar hormone binding marcomolecule was also found in mitochondria from rabbit kidney, as well as human liver and kidney. In the rat this saturable thyroid hormone binding component was found in mitochondria from liver, kidney, myocardium, skeletal muscle, intestinal mucosa, whole small intestine, adipose tissue, and lung. It was absent from the mitochondria of adult brain, spleen and testis, organs known to be calorigenically unresponsive to thyroid hormones injected in vivo. In contrast, neonatal rat brains contain the protein with binding constants similar to those of neonatal or adult rat liver mitochondria, but in older rat brains (14 and 17 days) the saturable binding was no longer present, as in adult brain. These data provide strong support for the biological relevance of the mitochondrial component as a thyroid hormone receptor.

Animals↗
PubMed1977

Thyroid hormone action: the mitochondrial pathway.

The subcellular compartments have been investigated to compare proteins capable of binding triiodothyronine and thyroxine; specific binders have been found in cytosol, nuclei, and mitochondria from rat liver and kidney. The binding protein from the inner mitochondrial membrane had the highest association constant (greater than 10(11) liters per mole), suggesting possible direct hormone action on the mitochondria. Binding of hormone analogs was found to be related to known physiological potency, and stereospecific discrimination between L- and D-thyroxine was observed. The saturable receptor was found in the mitochondrial membranes of rat liver, kidney, myocardium, and skeletal muscle but not in mitochondria from the unresponsive tissues: brain, spleen, and testis. Oxidative phosphorylation by mitochondrial vesicles from hypothyroid rats increased after the addition of physiological concentrations of triiodothyronine, which corroborated direct hormone action on mitochondria.

Animals↗
PubMed1975

Thyroid hormone binding by a component of mitochondrial membrane.

The thyroid hormone, triiodothyronine, has been shown to be bound by the intranuclear chromatin protein associated with active DNA, where it is believed to stimulate transcription. Evidence exists that the thyroid hormones have direct action not only on nuclei, but also on mitochondria. Threfore, specific proteins that bind thyroid hormones in the mitochondria should be demonstrable. Mitochondria were isolated from homogenized rat livers by sedimentation through 0.25 M sucrose solution, followed by washing four times to free them of microsomes. Strong binding of thyroid hormones was observed in mitochondrial fractions prepared from both the membranes and the matrix. After incubation in an ice bath with increasing amonts of triiodothyronine with added tracer [125I]triiodothyronine, the matrix infrequently contained specific saturable receptor sites, but usually exhibited strong "nonspecific" interaction...

Animals↗
PubMed1975

Serum triiodothyronine concentration in thyroid storm.

Serum triiodothyronine levels were elevated in 6 patients with thyroid storm (769 plus or minus 181 ng/100 ml) but the values observed were not significantly different from those found in uncomplicated thyrotoxicosis (752 plus or minus 282 ng/100 ml). This observation suggests that the pathogenesis of thyroid storm resides in mechanisms other than a simple increase in serum triiodothyronine concentration.

Adolescent↗