SOME ASPECTS OF THE METABOLISM OF SULFATE-S(35) AND CALCIUM-45 IN THE METAPHYSES OF IMMATURE RATS : INFLUENCE OF β-ESTRADIOL BENZOATE

Weanling rats were given 2 mg. of 17-β-estradiol benzoate at weekly intervals for 4 weeks. Twenty-four hours after each intraperitoneal injection of the estrogen 100 µc. of S(35)-sulfate or 11 µc. of Ca(45) was similarly injected. The animals were sacrificed 24 hours after the last dose of isotopes. An effect of estradiol benzoate on calcium metabolism was deduced from the observation that the concentration of calcium in some tissues of the treated rats was higher than the concentration in the tissues of untreated rats. Alkaline extracts of the distal metaphyses of femurs from the estradiol-treated and from control rats, given S(35)-sulfate, were shown by chromatography on an anion exchange resin to contain from 9 to 22 per cent of the S(35) as inorganic sulfate. From similar bone samples, 6 to 21 per cent of the S(35) was removed by decalcification with sodium versenate. Most of the remaining S(35) was associated with uronic acid and hexosamine; on paper chromatograms and paper electrophoretograms S(35) was shown to be part of material which migrated and was metachromatic in the same way as purified chondroitin sulfate. Autoradiograms of the proximal ends of tibiae from the animals given estradiol benzoate showed that both the S(35) and Ca(45) were deposited in the metaphyses in strata. The arrangement of the strata of S(35), however, was different from the arrangement of the strata of Ca(45). This difference in arrangement is interpreted as indicating that most of the S(35) in the metaphysis was derived from the chondroitin sulfate of the cartilage plate which the metaphysis had replaced.