Mitochondrial binding sites for triiodothyronine.

Metabolic effects upon rat liver mitochondria have been observed by others within 2 min of injection of massive amounts of L-T4. Reported here is the subcellular distribution of 2--5 ng high specific activity [125I]L-T3 2 min after ip injection with and without a loading dose of 30 micrograms unlabeled T3. The loading dose did not change the hormone concentration in the livers of normal or thyroidectomized rats, but it decreased the amount of hormone found in the nuclei in both groups and it increased the mitochondrial hormone only in the normals. The amounts of hormone in the nuclear and mitochondrial fractions were considerably higher in hypothyroid animals than in normals. By chromatography, over 90% of mitochondrial 125I was T3. The 125I content of Triton X-100 extracts of mitochondrial membranes was not affected by stable T3 in vivo or in vitro. It was concluded that specific high affinity, low capacity mitochondrial binding sites could not be found 2 min after hormone injection when specific nuclear binding sites are already evident. Specific binding may not be essential for the rapid effects of thyroid hormones upon rat liver mitochondria.     

African Americans' access to healthy food options in South Los Angeles restaurants

OBJECTIVES: We examined availability and food options at restaurants in less affluent (target area) and more affluent (comparison area) areas of Los Angeles County to compare residents' access to healthy meals prepared and purchased away from home. We also considered environmental prompts that encourage the purchase of various foods. METHODS: We designed an instrument to assess the availability, quality, and preparation of food in restaurants. We also assessed advertisements and promotions, cleanliness, and service for each restaurant. We assessed 659 restaurants: 348 in the target area and 311 in the comparison area. RESULTS: The nutritional resource environment in our target area makes it challenging for residents to eat healthy away from home. Poorer neighborhoods with a higher proportion of African American residents have fewer healthy options available, both in food selections and in food preparation; restaurants in these neighborhoods heavily promote unhealthy food options to residents. CONCLUSIONS: Environment is important in understanding health status: support for the healthy lifestyle associated with lower risks for disease is difficult in poorer communities with a higher proportion of African American residents.