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We studied body composition, white and brown adipose tissue cellularity, lipoprotein lipase activity and metabolic enzyme activity in three groups of rats: nonpregnant controls, lactating dams and nonlactating dams (i.e., dams not permitted to suckle their young). Nine to 11 rats in each group were killed on d 12 postpartum (study d 34) and on d 40 postpartum (study d 62). During lactation, brown fat citrate synthase, beta-hydroxyacylCoA dehydrogenase (HOAD) and lipoprotein lipase activities were significantly lower in the lactating than in the nonlactating dams or virgin controls. Although the nonlactating dams had their pups removed within 24 h after delivery, by d 12 postpartum citrate synthase and HOAD activities were significantly lower than those of nonpregnant controls. By the end of the study there were no differences among the three groups except in the case of HOAD. HOAD activity in the lactation group was significantly lower than in the nonlactation group. White fat cell number in the parametrial depot was significantly increased in the nonlactation groups by d 12 postpartum. In the lactation group, increased white fat cell number in this depot was detectable at d 40 postpartum, when carcass fat stores and fat cells had been repleted. These results demonstrate that both lactating and nonlactating dams undergo cellular hyperplasia, at least in the parametrial depot. This may predispose them to obesity. Also, decreased brown fat metabolism in the nonlactating dams may be contributing to their significantly greater carcass fat content at d 12 postpartum.

This report describes the novel development of an animal model for neonatal carnitine deficiency using the artificially fed newborn rabbit. Each litter was separated from the mother following the first colostrum feeding and divided into 2 groups, one of which was fed a purified rabbit formula that was essentially free of carnitine; the other received the same formula supplemented with L-carnitine (100 mg/l). At 9-13 d of age, rabbit pups receiving the carnitine-free formula had lower concentrations of total, free and acylcarnitine in plasma and urine, as well as lower total acid soluble carnitine concentrations in liver, muscle, heart and brown adipose tissue than those receiving the same formula supplemented with L-carnitine. Their plasma and tissue levels were also lower, but their urinary carnitine concentrations were higher than those in naturally-raised pups. The findings suggest that the described animal model may prove to be a useful tool for the investigation of certain aspects of neonatal carnitine deficiency.

A photodetection device permitting rapid and direct photographic recording of light emission from luminol-based immunodot and Western blotting assays is described in detail. This device permits contact exposure on Polaroid film of luminescent samples on nitrocellulose strips, and thus obviates the need for darkroom and film processing facilities. Immunodetection of mouse alpha-fetoprotein in brown fat homogenate and immunoglobulin E in nonimmune human sera employing luminol-based Western blotting and immunodot assays were used to demonstrate the versatility and operational simplicity of the detection device. The use of the detection device in combination with luminol-based immunoassays resulted in greater signal intensities and increased sensitivity over that attainable with the commonly used chromogenic substrate, 4-chloro-1-naphthol.

A fast single-step lipid extraction procedure and high-performance liquid chromatography with in-line uv and electrochemical detection are used for the simultaneous quantitative determination of tocopherols, ubiquinols, and ubiquinones in blood, plasma, tissue homogenates, and subcellular fractions. The compounds of interest can be quantitatively extracted into hexane from a sodium dodecyl sulfate-treated aqueous homogenate after precipitation of protein by addition of an equal volume of ethanol. alpha-, gamma-, and delta-Tocopherol, ubiquinol 9, ubiquinol 10, and ubiquinones 9 and 10 can be well separated on a reversed phase column. Ubiquinones are detected at 275 nm by the uv detector, and ubiquinols and tocopherols by the electrochemical detector in the oxidative mode. Quantitation is done by comparing chromatographic peak heights to those of a standard solution containing known amounts of tocopherols, ubiquinols 9 and 10, and ubiquinones 9 and 10, analyzed under identical conditions. The high sensitivity of the electrochemical detection allows operation at low potentials (+0.5 V) with low detector response, but high selectivity for the easily oxidizable tocopherols and ubiquinols and decreased baseline noise. The uv detection limits the overall sensitivity of the procedure to 2 pmol ubiquinone, corresponding to 0.1 microM ubiquinone in the lipid extract. The ranges of values obtained for rat and guinea pig tissues, for rat liver mitochondria, and for blood and plasma from rats and humans are given.

The total nitrogen and L-hydroxyproline concentrations of two intra-abdominal and two subcutaneous sites of adipose tissue were measured in male and female Wistar rats. At 100 g body weight the nitrogen concentration of intra-abdominal adipose tissue was slightly lower than that of subcutaneous adipose tissue. As age advanced beyond sexual maturity, the nitrogen content of intra-abdominal adipose tissue was steadily reduced, whereas that of subcutaneous tissue did not change. The L-hydroxyproline concentration of intra-abdominal adipose tissue was also lower than in subcutaneous adipose tissue. In male rats it rose in most adipose tissue sites when sexual maturity was reached, then fell with advancing age. In female rats the pattern of change was less consistent, but the l-hydroxyproline content of intra-abdominal adipose tissue was reduced as age increased.