Synthesis of Heparin-Like Glycosaminoglycans in Rat Ovarian Slices1

Rat ovarian slices incubated in a medium containing essential amino acids and glucose incorporated 35S (Na235SO4) into sulfated glycosaminoglycans (S-GAG) at a near linear rate for 12 h. S-GAG consisted of 1) HNO2-sensitive heparin-like substances (ca. 60%) resembling in electrophoretic behaviour heparan sulfate (major component) and heparin of M.W. <12,000 (minor component); 2) a fraction sensitive to testicular hyaluronidase (ca. 15%); and 3) a fraction resistant to both treatments (ca. 25%). The identification of fractions 2) and 3) as chondroitin 4-sulfate + chondroitin 6-sulfate and dermatan sulfate, respectively, was confirmed by electrophoretic analysis. The same pattern of 35S-GAG was also found after intraperitoneal administration of 35SO4 to sexually mature rats. Pulse-chase experiments in tissue slices revealed that the major sites of 35SO4 incorporation were the granulosa and thecal cells of antral follicles. Secreted material appeared in the antrum 30 min after the onset of the 10 min pulse and increased in concentration during the subsequent 4–8 h. Preantral and atretic follicles, corpora lutea, interstitial tissue and oocytes were poorly labeled. S-GAG production/unit tissue protein was about 3-fold higher in immature (20-day-old) than in mature animals. Addition to the incubation medium of luteinizing hormone (LH; 10 µg/ml) or progesterone (10 µg/ml) suppressed 35S incorporation into GAG. The progesterone effect had a shorter latency than that of LH, suggesting that the steroid may mediate this action of LH. It is proposed that the presence of heparin-like substances in follicular fluid and hormone-induced changes in their concentration may play a part in ovulation-related events.