Ovariectomy of newborn rats: a descriptive surgical procedure.

The ovaries of newborn rats were removed through an opening in the external abdominal oblique muscle, lateral to a dorsal midline skin incision. This approach diminished the incidence of postsurgical hernia by avoiding the exertion of intraabdominal pressure and visceral weight on a ventral midline incision. Loss of abdominal fluid, which usually occurs with ventral midline incision, also was avoided.

Absorption, distribution, and excretion of [14C]patulin by rats.

Adult rats of both sexes were given a single oral dose of [14C] patulin and were sacrificed at various time intervals from 4 hr to 7 days following administration of the mycotoxin. Two groups of rats were employed; the treated group had been exposed to daily oral doses of unlabeled patulin (dissolved in pH 5.0 citrate buffer) in utero and for 41-66 wk after weaning, while the controls were given the buffer only throughout gestation and for 38-81 wk after weaning. Approximately 49% of the administered 14C radioactivity was recovered from feces and 36% from urine within 7 days after dosing. Most of the excretion of labeled material occurred within the first 24 hr. All of the 14C activity detected in the urine samples was either metabolites and/or conjugates of the original [14C]patulin. About 1-2% of the total radioactivity was recovered as 14CO2 from expired air. Carbon-14 radioactivity in various tissues and organs was determined throughout the 7 day period; the most significant retention site was the red blood cells.

Acute, subacute, and residual effects of polychlorinated biphenyl (PCB) in rats. I. Biologic half-life in adipose tissue.

Sprague-Dawley rats were fed diets containing Aroclor 1254 at o, 5, 50, or 500 ppm for 4 wk. The biologic half-life of Aroclor 1254 in adipose tissue of rats fed 500 ppm, as determined by a gas chromatographic method, was 8 wk in males and 12 wk in females. These results are in line with sex-linked differences reported previously for other chlorinated hydrocarbons. It appears that the lower chlorine homologs in the Aroclor mixture are metabolized while those with higher chlorine content are lost more slowly.

Acute, subacute, and residual effects of polychlorinated biphenyl (pcb) in rats. II. Pathology and electron microscopy of liver and serum enzyme study.

This study was undertaken to determine the residual effects of a polychlorinated biphenyl (Aroclor 1254) fed to male rats at dietary concentrations of 0, 5, 50, and 500 ppm in diet. The animals were treated for 4 wk (acute and subacute phase), then observed for periods of up to 50 wk following termination of exposure (residual phase). The most significant histopathologic alteration was fatty degenerative change in the liver, which was most marked at 9 wk. Forty-six weeks postexposure, more than 50% of the rats fed 500 ppm still demonstrated fatty degenerative changes. On electron microscopic examination, marked increases in lipid vacuoles and smooth endoplasmic reticulum (SER) occurred with a concomitant decrease in rough endoplasmic reticulum (RER) profiles in the animals receiving 50-500ppm for 4 wk. Thirty-seven weeks following the exposure period, rats dosed with 50 ppm showed partial recovery toward control morphology (less lipid, less SER, more RER), while those receiving 500 ppm did not. Persistent morphologic alterations included an increase in SER and medium-density lipid material within cisternae of Ser, Golgi and Golgi-condensing vesicles, as well as a decrease in parallel arrays of RER. The persistence of ultrastructural alteration throughout the 46-wk residual phase emphasizes the long-lasting effects of 4-wk exposure to polychlorinated biphenyl.