Abstract
Summary
The normal growth of the mammary glands of male rats of the Sprague-Dawley-Rolfsmeyer strain was compared to that induced by 1 μg/day of estradiol benzoate (EB) from 40 to 80 days by the DNA method. The mean DNA/100 g BW of the normal male rat at 40 days of age was 2.25 mg, at 60 days, 2.90 mg, an increase of 28.8%, and at 80 days, 2.87 mg. The rats injected with EB from 20 to 40 days had a mean DNA/100 g BW of 1.92 mg, 0.33 mg less than the controls. After 40 days of EB (age 60 days), the mean DNA was 2.33 mg still, 0.57 mg less than the control group. After 60 days of EB (age 80 days), the mean DNA was 3.0 mg, the same as the controls, and 28.7% greater than the previous level. This level of DNA is equal to that present in mature ovariectomized female rats.
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