| Abstract: | Cattle implanted with Ralgro (zeranol) or Synovex-S (estradiol/progesterone, 20:200, w/w) reach finishing weight sooner than controls. Further, it is generally agreed that this increase in weight cannot be attributed to increased fat deposition in Ralgro implanted cattle. However, the effects of Ralgro or Synovex-S on intramuscular lipid or cholesterol have not been reported. Therefore, the effects of Ralgro or Synovex-S implants on intramuscular cholesterol and lipid in longissimus dorsi muscle from mature steers were studied. Lipids were extracted into chloroform from muscle which was trimmed of extramuscular fat. Extracted lipids were evaporated under nitrogen, and quantitated by gravimetric determination. Cholesterol contents were determined spectrophotometrically using a colorometric method. Intramuscular lipid composition was not significantly (p≤.05) lower in implanted animals compared to controls. Cholesterol levels were also not affected significantly by the Ralgro or Synovex-S implant. Although trends were reproducible, 40-116 steers per treatment would be required to obtain statistically significant results (p≤.05). Using the VAX 11-750 computer, crystalline structures of zeranol and 17 estradiol were obtained from the Cambridge Data Base. With computer modeling techniques it was possible to superimpose these two compounds and to demonstrate analogous molecular configurations. Based on these data, studies are in progress to investigate the possibility that zeranol stimulates cell division in Swiss 3T3-L1 cells as has been demonstrated for 17 estradiol. |
|---|