Male Rats Body Weight Research Articles

Effects of cholesterol feeding on the bile acids of male and female germ-free rats.

The effect of cholesterol feeding on the intestinal bile acids was studied in male and female germ-free rats. The bile acid pattern of the male animals was not altered considerably by cholesterol supplementation. Bile acids belonging to the chenodeoxycholic acid pathway slightly increased whereas cholic acid decreased. beta-Muricholic acid remained the predominant bile acid in male rats. On the other hand, cholesterol feeding to female germ-free rats substantially changed the intestinal bile acid composition. The concentration of cholic acid fell to one third and that of beta-muricholic acid decreased by about half. On the contrary, the relative amounts of chenodeoxycholic acid, allochenodeoxycholic acid and alpha-muricholic acid increased several times. The most striking sex-linked effect of cholesterol feeding was the occurrence in female rats of a bile acid tentatively identified as 3 alpha, 7 beta-dihydroxy-6-oxo-5 beta-cholan-24-oic acid. This bile acid accounted for 16.0% and 26.6% of the total bile acids in the small intestine and in the cecum plus large intestine, respectively. Cholesterol feeding also influenced the sulfation of bile acids in female germ-free rats. In the small intestine the sulfated fraction increased from 1.1% to 2.8% and in cecum plus large intestine from 23.0% to 30.8%. Allochenodeoxycholic acid was the predominant bile acid in the sulfate fraction. The total amount of bile acids in cecum plus large intestine increased from 72.0 to 225.0 mg/kg body weight in male rats and from 64.8 to 231.3 mg/kg body weight in female animals.

Digestibility in male rats with lateral hypothalamic lesions

The body weight of male rats with lateral hypothalamic lesions remained approximately 20% below that maintained by nonlesioned controls. One month following surgery, both food intake and energy losses in feces and urine were measured in all animals for five days. The percentage of ingested food absorbed by the gut (“digestibility”) was determined from calorimetric analysis of the feces to be slightly, though significantly, higher for the lesioned animals (79.7% vs 77.4%). Resorptive capacity, as indicated by the percentage of absorbed energy lost in the urine, was determined to be the same for the lesioned and control animals (4.8% vs 4.5%). These results indicate that the digestive, absorptive, and resorptive processes of LH-lesioned animals are at least as efficient as those of nonlesioned animals maintaining normal body weights. Thus, though LH-lesioned animals are reported to display various gastrointestinal dysfunctions, alterations in digestive or resorptive efficiency are apparently not responsible for their chronically-reduced body weights.

1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid (DICA), an exfoliative antispermatogenic agent in the rat.

The oral administration of 50 mg DICA/kg at nine weekly or four monthly intervals produced partially reversible infertility in male rats as judged by the results of serial mating and testicular histology. Oral 500 mg DICA/kg doses administered at the same intervals produced permanent sterility. Single oral doses of 50 or 500 mg DICA/kg elevated mean FSH concentrations on days 2, 3, and 7 but did not affect LH or testosterone. Mean plasma concentration peaked at 74 micrograms/ml 4 hr after a 50 mg/kg dose of uniformly tritiated DICA; 24 hr later, it had declined rapidly to 5.5 micrograms/ml. The drug did not have a strong affinity for any tissue studied including the testis. DICA-induced exfoliation of immature germ cells was first observed 4 hr after administration and led to significantly reduced testis weights by day 2. Neither single doses of 10--250 mg DICA/kg nor five daily doses of 10--100 mg DICA/kg reduced seminal vesicle, ventral prostate, or body weights of male rats. Chronic weekly DICA administration did reduce mean seminal vesicle weight. These studies have shown that DICA is an effective, partially reversible antifertility agent that directly affects the rat testis.

Androgenic control of food intake and body weight in male rats.

Castration of adult male rats produces a delayed (by approximately 1 mo), permanent hypophagia and reduction in weight gain. This contrasts with the rapid, transient hyperphagia and increased weight gain caused by ovariectomy in female rats. Injections of testosterone propionate (TP) stimulate food intake and weight gain in castrated males. Neither 5alpha-reduction nor aromatization of the testosterone molecule plays an important role in the stimulation of these measures by TP. The 5alpha-reduced metabolite of TP, 5alpha-dihydrotestosterone propionate (DHTP), is less effective in increasing eating and weight gain than is TP. Very high doses of TP may actually reduce weight gain with prolonged treatment (2-6 wk). It is likely that this reduced weight gain is due to aromatization of TP to an estrogen. The nonaromatizable androgen, DHTP, does not reduce weight gain even in very high doses, and concurrent progesterone injections reverse the weight-reducing actions of high TP doses.

The effect of lucerne-protein concentrate in the diet on growth, reproduction and body composition of rats.

1. Protein concentrates were prepared from freshly cut lucerne by the Pirie process and freeze-dried. When supplemented with methionine or cystine and given to rats as the sole source of protein at 120 g protein/kg diet, the adjusted mean protein efficiency ratio was 2.89 (casein standard at 2.50). As a supplement to protein from barley meal the lucerne leaf-protein concentrate (LPC) was similar to casein.2. To investigate nutritional safety, lucerne LPC supplemented with methionine was given to rats at high levels for 6 months; exposure of these rats to diffuse daylight was avoided to prevent a severe disfiguring photosensitivity reaction. At a dietary protein concentration of 100 g/kg, rats grew equally well with lucerne LPC or casein. When the supplement was given at protein concentrations of 200 or 300 g/kg the rates of body-weight gain of male and female rats were less than those of control rats given casein. However, after 5 months on the diets, body-weights of male rats had nearly reached those of the controls.3. Apparent protein digestibility ratio was about 0.80 with all three levels of lucerne LPC.4. Reproduction was normal in seventeen of the eighteen female rats given the lucerne LPC at the three levels; lactation was also normal and litters were successfully raised to weaning.5. Organ weights, liver histology and blood haemoglobin were normal in male rats given the lucerne LPC for 6 months.6. Total body lipid of male rats given lucerne LPC was about half that of the control rats given casein. Body protein was slightly increased, and moisture content was higher in rats given lucerne LPC.7. The ‘whey’ remaining after precipitation of the protein from lucerne juice strongly inhibited the initial growth of mice given a complete control diet. The mice soon accommodated to the depressive effect of ‘whey’, and body-weight gains were normal during the 3rd week.

Fensulfothion

Abstract The acute oral LD50 of both fensulfothion and fensulfothion sulphone was between 6 and 10 mg active ingredient (a.i.)/kg body weight for male rats and between 2 and 3 mg a.i./kg body weight for female rats. For ewe hoggets, the acute oral LD50 of fensulfothion was between 3 and 4 mg a.i./kg body weight. Administration of fcnsulfothion daily at dose rates of 3, 2, I, and 0.5 mg a.i./kg body weight caused death in 2, 4,7, and 13 days respectively. Of 3 other ewe hoggets drenched daily for 20 days at the rate of 0.5 mg a.i./kg body weight, one died, one became moribund, and one survived. No residues of fensulfothion or its oxidation products were detected in samples of fat, muscle, and liver from the latter 3 sheep. In a replicated plot trial pasture was topdressed with pellets of 5% fensulfothion at rates of I Ib and 2 Ib a.i./acre. After 4 weeks the pastures contained residues of 0.4 and 1.0 parts per million fensulfothion respectively. In a second trial, pasture topdressed at the rate of 2 Ib a.i./acre contained 1.1 parts per million fensulfothion after 4 weeks.

The senescent loss of body weight in male rats.

The senescent loss of body weight in male rats.

Animal Behavior and Internal Drives

Animal Behavior and Internal Drives