Summary
Six 8-day-old female calves were treated with a subcutaneous implant of 200 mg testosterone
+ 20 mg estradiol-17β. Thirty-five days following implantation, plasma lipoproteins
were compared to those in control calves of the same age. The LDL exhibited a slight
change in protein and lipid concentrations and no change in particle size. The effects
of steroid therapy on HDL and particularly on the lighter density HDL were characterized
by a reduction of densities associated with a decrease in protein content, and by
a rise in lipids and an increase in particle size. The changes in HDL composition
but not in LDL alterations were consistent with those associated with sexual maturation
described previously. Although testosterone is the predominant component of our combined
preparation, the effects of our treatment on young female calves is not consistent
with the data reported for human lipoproteinemia. The high levels of urinary estradiol
in treated calves suggest that these effects result more likely from the aromatization
of the injected testosterone.
Key-Words
Lipoproteins - Image Analysis - Steroids - Calves
