Marginal copper deficiency in rats. Aortal morphology of elastin and cholesterol values in first-generation adult males.

A marginal, 2 parts per million (ppm) copper diet (experimental) was fed to female rats for 4 months prior to breeding, through gestation/lactation, and to the weaned offspring to determine the consequences in adult, male offspring on cholesterol values and aortal morphology. Liver copper concentrations of the dams and pups at day 21 of lactation and of the 117-day-old offspring who consumed the experimental diet were lower (P less than 0.0001) than corresponding rats fed a 10 ppm copper diet (control). However, statistically significant differences due to dietary treatments were not evident in pre- or post-weaning gain in body weight, litter size, cannibalism of pups, or total cholesterol concentrations of the serum and aorta. Ultrastructural examination of experimental offspring aortas revealed focally abnormal features of endothelial cells, the subendothelial space, collagen fibers, smooth muscle cells, and particularly elastin. The ultrastructural irregularities of elastin included discontinuous regions of the internal elastic lamina comprised of stained clumps of elastin of irregular size and shape. The results of this study suggest that a marginal copper nutriture begun in utero will elicit morphologic abnormalities of the aorta in rats that are otherwise without overt signs of copper deficiency.

Tetramine cupruretic agents: a comparison in dogs.

The cupruretic effects of 2 tetramine (N,N'-bis (2-aminoethyl) alkane diamine) chelators were examined in healthy dogs fed a commercial dog food containing 12.2 micrograms of copper/g of dry diet. Two groups of 3 dogs each were given either 300 mg of 2,2,2-tetramine tetrahydrochloride or 2,3,2-tetramine tetrahydrochloride for 23 consecutive days. Serum and 24-hour urine samples obtained before drug administration and during therapy were analyzed for copper, zinc, and iron concentrations. Both tetramines produced a significant cupruresis without significant changes in serum copper or in serum or urine zinc and iron concentrations. The 2,3,2-tetramine tetrahydrochloride produced a 4- to 9-fold greater cupruresis than did 2,2,2-tetramine tetrahydrochloride and resulted in a daily loss of more than 2 mg of copper in the urine. The dogs had no laboratory or clinical evidence of toxic side effects to either cupruretic agent during the treatment period. The results of the present study indicate that 2,3,2-tetramine should be an effective decoppering drug for use in dogs.

Use of 2,3,2-tetramine as a hepatic copper chelating agent for treatment of copper hepatotoxicosis in Bedlington terriers.

Five Bedlington Terriers with inherited copper (Cu) hepatotoxicosis and with hepatic Cu concentrations ranging from 3,000 to 11,000 micrograms/g of dry weight (normal, less than 350 micrograms/g of dry weight) were treated daily for up to 200 days with 2,3,2-tetramine tetrahydrochloride. During treatment, no change was made in the dietary Cu intake, which ranged from 12 to 16 micrograms/g of dry diet. Concentrations of hepatic and serum Cu, iron, and zinc were determined before and at the conclusion of the treatment period. In one dog, 24-hour urinary Cu concentration was measured before and during treatment. A liver biopsy specimen obtained after treatment had significantly (P less than 0.05) reduced hepatic Cu concentration (3,282 micrograms/g of dry weight; a 54.9% reduction), compared with the pretreatment value (7,281 micrograms/g of dry weight). After treatment, there was an overall general lessening of the extent of hepatic morphologic damage. Cytochemical examination for Cu in rhodanine-stained biopsy specimens revealed decreased numbers of Cu-laden hepatic lysosomes. The mean daily urinary Cu concentration increased as much as 25-fold during 2,3,2-tetramine treatment. Hepatic iron and zinc concentrations and serum Cu concentrations remained within normal ranges after treatment. Clinical or laboratory evidence of 2,3,2-tetramine toxicosis was not detected during treatment. These findings indicated that in affected Bedlington Terriers, 2,3,2-tetramine was a safe and rapid chelating agent of hepatic Cu.

An inexpensive caging method for miniature swine suitable for trace-element studies.

An inexpensive and durable caging system for swine was developed for trace-element studies. The caging system has proven to be suitable for up to four miniature swine and was housed in a barn.

Dietary L-histidine-induced hypercholesterolemia and hypocupremia in the rat.

The effect of histidine-supplemented stock diets on plasma cholesterol and on the amelioration of the hypercholesterolemia by simultaneous copper supplementation was examined in rats. Weanling male Sprague-Dawley rats, five groups of 10 animals each, were fed ground stock diets unsupplemented or supplemented with 8% L-histidine, 8% L-histidine plus 222.8 micrograms Zn/g and 8% L-histidine plus 56.6 micrograms Cu/g. On day 46 plasma and liver cholesterol, copper and zinc concentrations were determined by colorimetry and atomic absorption spectrophotometry. Histidine supplementation produced hepatomegaly, depressed growth, a 131.8% (P less than 0.001) increase in plasma cholesterol and significant reductions in plasma copper and zinc and liver copper concentrations. The simultaneous feeding of histidine and zinc-supplemented stock diet failed to alter the hypercholesterolemia despite elevation in plasma zinc to values in excess of control animals. The simultaneous feeding of histidine and copper-supplemented stock diets abolished the hypercholesterolemia, reduced the hepatomegaly observed with histidine alone and elevated tissue copper concentrations to values in excess of control animals. Tissue copper and cholesterol concentrations showed significant negative correlations. No correlations between zinc and cholesterol were observed. The results suggest that histidine-induced hypercholesterolemia is due to changes in copper status, and is abolished by simultaneous copper supplementation.

Dietary protein quality, protein quantity and food intake: effects on lactation and on protein synthesis and tissue composition in mammary tissue and liver in rats.

Rate of protein synthesis in mammary tissue and liver as well as pup weight and milk yield were measured at d 15 of lactation in rats fed throughout gestation and lactation diets that varied in protein quality (wheat, wheat supplemented with lysine and threonine or casein supplemented with methionine), protein quantity [11 or 21% (wt/wt)] and feeding level (ad libitum or pair-fed to 100 or 85% of the consumption of dams fed wheat ad libitum). Improvement in dietary protein quality or quantity at the ad libitum feeding level produced large increases in mammary protein synthesis and pup weight; pair-feeding at 100 or 85% of the ad libitum wheat consumption level reduced or eliminated these increases. Increases in protein synthesis and pup weight associated with protein quality improvement were of similar magnitude to those associated with nearly doubling protein content of maternal diets. The responses of liver protein synthesis to dietary manipulation were qualitatively similar to those seen in mammary tissue. These data demonstrate that maternal dietary protein quality, protein quantity and feeding level all affect mammary protein synthesis and pup weight, and that, considered across all diets, changes in mammary protein synthesis are highly correlated with changes in pup weight and protein nutritional value.