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Cell cultures of ovine pituitaries were maintained for up to 3 weeks. A specific double antibody radioimmunoassay was used to measure FSH in the media and cells. The rate of FSH synthesis increased in the cultures during the first 4-6 days to a level of approximately 50 ng/day/106 cells, generally remained constant for 2 weeks and then decreased. The FSH produced in vitro migrated similarly to highly purified ovine FSH on P-60 polyacrylamide gel filtration columns and had a biological potency essentially identical to that of the highly purified FSH standard. Addition of 17beta-estradiol (E2) at 10-9M on days 2 or 6 incubation decreased FSH synthesis greater than 95% within 30 h. Time-course analysis revealed that the effect of E2 can be observed as early as 6 h after treatment. FSH synthesis resumed after removal of E2 and reached control levels within 6 days. The lowest effective dose of E2 was 10-11M; E2 at 5 X 10-11M maintained FSH production at approximately 50% of the control levels. Diethylstilbestrol was as active estriol was 1/10th as active and 17alpha-estradiol was 1/100th as active as E2. Progesterone (P), 5alpha-pregnane-3,20-dione (5alphaDHP), 20alpha-hydroxy-pregn-4-en-3-one(20alpha-OHP), testosterone, 5alpha-dihydrotestosterone and corticosterone had no effect on FSH levels. These findings suggest that estrogen is capable of playing a major role in FSH synthesis and release by action directly at the pituitary level.

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Acetone precipitates of bovine follicular fluid from small (3-5 mm) and large (10-20 mm) follicles were fractionated by nondissociative procedures involving chromatography on Sephacryl S-300, DEAE cellulose, and Sepharose CL-2B. Most of the proteoglycan material eluted with a relatively low molecular weight (Kav = approximately 0.6) from Sepharose CL-2B. Comparisons of the proteoglycans from small versus large follicles showed respective differences of 20 versus 34% protein, 74 versus 48% chondroitin sulfate-B, and 4 versus 8% other sugars. The protein moiety of the proteoglycan from small follicles exhibited greater proportions of aspartic acid, serine and glycine, but lower proportions of theonine, alanine and valine, than its analog from large follicles. Chromatography on Sepharose CL-2B in 4 M guanidine-HCl failed to alter the elution position of the proteoglycans. However, noticeable decreases occurred in the protein and total amino acid content of the proteoglycans, especially from large follicles, suggesting preparations obtained from the nondissociative procedures contained aggregates of peptides, glycosaminoglycans, and/or proteoglycan fragments. Proteoglycans from both sizes of follicles were enriched in serine, glutamic acid and glycine, but diminished in leucine and lysine following the dissociative gel filtration. Differences in composition of the proteoglycans may be related to follicular differentiation.

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