A comparison of 131-I-triiodothyronine accumulation and degradation in ethanol-treated and control rats

Hormone-specific alterations of T4, T3, and reverse T3 metabolism with recent ethanol abstinence in humans

Effects of recent alcoholic withdrawal on thyroxine (T4), 3,5,3'-triiodothyronine (T3), and reverse T3 (rT3) metabolism were determined by serum tracer kinetic studies in recently abstinent alcoholics without overt hepatocellular injury or caloric deprivation. Data were compared with those of normal subjects using a three-pool model, with rapidly and slowly equilibrating pools exchanging with serum. Significant differences included 1) reduced serum total rT3 levels (to 69% of normal) and rT3 degradation rates (to 61%); 2) increased rT3 binding in rapidly (to 557%) but reduced binding in slowly (to 13%) equilibrating tissues, with opposite effects on rT3 fractional transfer rates to serum from rapidly (to 7.5%) and slowly equilibrating sites (to 669%); 3) increased T4 fractional transfer rates from serum to rapidly equilibrating tissues (to 122%); and 4) increased T4 binding to both rapidly (to 195%) and slowly (to 190%) equilibrating tissues. T3 kinetics were not significantly altered. Thus recently abstinent alcoholics have hormone-specific alterations of T4, T3, and rT3 transfer, distribution, and metabolism distinct from other nonthyroidal illnesses or caloric deprivation. Furthermore, these data indicate separate transfer processes for T4, T3, and rT3 from serum to tissue sites and hormone-specific tissue binding characteristics in humans in vivo.

The effects of acute and chronic morphine treatment on the process of facial nerve regeneration

Prominent cellular responses to axonal interruption include enhanced synthesis of RNA and protein in the neuronal perikaryon, and proliferation of reactive Schwann cells. Since morphine has been shown to significantly depress cellular metabolism, we examined its effect on these and other reparative responses underlying nerve fiber regeneration. Rat facial nerve trunks from saline, acute morphine, and continuous morphine-treated animals were examined by light and electron microscopy at 3, 7 and 14 days after crush injury. The number of axonal sprouts/unit area and the diameters of regenerating axons were quantified at each survival interval. Both saline-treated and acute morphine-treated facial nerves demonstrated myelin degradation and Schwann cell hypertrophy (at 3 days post-axotomy), sprout outgrowth (at 7 days) and axon maturation and myelination (at 14 days). In the chronic morphine-treated animals, a retardation of the regenerative process was evident. Axon sprout outgrowth and axonal diameters were reduced at 3 and 7 days post-axotomy. In treated 14-day animals, axon diameters were normal; however, significantly fewer axon profiles/unit area were observed. After chronic morphine exposure, Schwann cell hypertrophy and proliferation, as well as myelin debris removal, were inhibited at all survival periods.

The effects of acute morphine treatment on the incorporation of [3H]L-lysine by normal and regenerating facial nucleus neurons

Although opiates significantly alter RNA and protein synthesis in a variety of neuronal cell types, their effect on the biosynthetic activity of regenerating neurons has not been investigated. In the present study, the effect of morphine on the incorporation of [3H]L-lysine into proteins of facial nucleus neurons was examined by light microscopic radioautography. Silver grains present within various compartments of normal and regenerating (3-, 7-, 14- and 21 days post-axotomy) neurons from saline-treated Wistar rats were compared with the amount present in similar cells from animals receiving 40 mg/kg morphine sulfate i.v. At 14- and 21-days post-axotomy, regenerating neurons were larger and the grain count in the emulsion over these cells was greater than that observed in normal (unoperated) neurons. In normal facial neurons, the accumulation of lysine into the nucleus and nucleolus was significantly lower 60 min after morphine administration. However, morphine's inhibition of lysine incorporation was even more pronounced in regenerating neurons. In these cells, nuclear lysine uptake was depressed at 3 and 7 days, while maximum inhibition of cytoplasmic incorporation occurred at 14-days post-axotomy. Morphine administration decreased nucleolar lysine incorporation at all survival intervals.

Strain differences in the response to morphine on incorporation of 3H-lysine into rat brain protein

The effect of morphine on the specific activity (SA) of lysine in the plasma free amino acid (FAA) fraction and in the cerebral cortical FAA and protein fractions, as well as on the specific accumulation and incorporation, was determined in male Sprague-Dawley and Wistar rats at various time intervals after intravenous injection of drug and amino acid into unanesthetized animals. The lysine SA was higher in Sprague-Dawley than in Wistar rats in the plasma and brain FAA fraction and in the protein fraction. In the SD strain, morphine decreased the SA of plasma FAA significantly, but had only slight effects in the Wistar strain. In the cortical gray matter, morphine elevated the SA of lysine significantly in both strains, although the rate of decrease of SA with increasing time after injection was different in the two strains. SA of the lysine in cerebral cortical protein increased in both strains with time, but did so more rapidly in the Sprague-Dawley strain. When the data for the free amino acids were expressed in terms of specific accumulation, the observed rates were higher in the Sprague-Dawley animals and reached a point of maximal concentration, which was not observed in animals of the Wistar strain. Morphine elevated the levels of specific accumulation of lysine into the cortical free amino acid pool in both strains of rat. However, specific incorporation of lysine into the cerebral gray cortical protein in control animlas was essentially similar in both strains. Despite the similarity in specific incorporation of lysine into brain protein in both strains of control rat, morphine treatment caused a much more marked inhibition of incorporation of lysine in the Wistar rats. Thus, it is concluded that Sprague-Dawley and Wistar rats are not equivalent in relation to the accumulation of an amino acid in the brain FAA pool from the plasma and that the effect of morphine on specific incorporation of lysine into brain protein is greater in Wistar rats.