Sulfated proteoglycans synthesized in myometrium of the estrogen-treated rabbit

Myometrium obtained from the estrogen-treated rabbit was incubated with [35S] sulfate, and the 35S-labeled proteoglycans were extracted from this tissue with 4 M guanidine hydrochloride. The extract was fractionated by CsCl density gradient centrifugation, followed by DEAE-cellulose column chromatography. The major proteoglycan fraction (D(1+2] was separated into two fractions (D(1+2)-I and D(1+2)-II) by gel filtration on Sepharose CL-4B. The compositions of the 35S-labeled glycosaminoglycans in 5 proteoglycan fractions (D(1+2)-I, D(1+2)-II, D3, D4, and D5) were analyzed by two dimensional cellulose acetate membrane electrophoresis after pronase digestion. All the fractions contained the 35S-labeled chondroitin sulfates A/C and heparan sulfate with the different proportions of the radioactivities. The results of the present study indicated that sulfated proteoglycans newly synthesized in myometrium of the estrogen-treated rabbit were considerably heterogeneous not only in the 35S-labeled glycosaminoglycan compositions but also in the molecular weight and buoyant density.