The Possible Role for a Follicular Protein in the Intraovarian Regulation of Folliculogenesis

diZerega, Gere S.; Campeau, Joseph D.; Ujita, Eryn L.; Kling, D.; Marrs, Richard P.; Lobo, Richard Roberto; Nakamura, Robert M.

doi:10.1055/s-2007-1022592

Cited by 22 publications

(5 citation statements)

References 46 publications

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“…Previously, we reported that this same fraction of folicular protein inhibited aromatase activity in intact granulosa cells (diZerega et al, 1983a, b, c, d). The portion of the gel exclusion HPLC eluent which inhibited the cell free placental aromatase assay was the same which inhibited whole porcine granulosa cell aromatase (Kling et al, 1984) and was the same which was secreted by human granulosa cells and contained aromatase inhibitory activity (diZerega et al, 1983b). Whether these are the same proteins remains to be determined after additional purification.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Placental Aromatase Activity in a Cell Free Assay by Ovarian Protein

Campeau¹,

Myint²,

Ono³

et al. 2009

Exp Clin Endocrinol Diabetes

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Previously we identified a fraction of follicular fluid (follicle regulatory protein: FRP) which inhibits granulosa cell aromatase activity. During the course of these studies the question of FRP acting via autocrine as well as paracrine mechanisms arose in addition to the need for a more efficient method of screening for aromatase inhibitory activity during the purification of FRP. Accordingly, we assessed the effects of FRP on aromatase activity in a microsomal assay. Placental microsome preparations were preincubated for 20 minutes with or without FRP prior to a 20 minute incubation with testosterone. Significantly less conversion of testosterone to estrogen occurred with FRP compared to control preincubation. When follicular protein was added without pre-incubation, there was no apparent change in microsomal aromatase activity, whereas after a 20 minute pre-incubation with the follicular protein fraction, significantly less testosterone was converted into estrogen. When various concentrations of FRP were assayed in the placental aromatase assay, a dose-response curve demonstrated a 50% inhibitory dose (ID50) of approximately 400 micrograms/ml. To further purify the aromatase inhibitory activity, 5 mg of the crude follicular fluid preparation was eluted through an anion exchange column via HPLC using a sodium acetate gradient. The fractions in the central elution peak contained aromatase inhibitor activity with ID50 values of 25-160 micrograms/ml. Thus Fractions were further purified by elution through a gel exclusion column via HPLC which demonstrated inhibition of cell free placental aromatase activity in the 15,000-18,000 molecular weight range with an ID50 of 5 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

Inhibition of Placental Aromatase Activity in a Cell Free Assay by Ovarian Protein

Campeau¹,

Myint²,

Ono³

et al. 2009

Exp Clin Endocrinol Diabetes

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“…We feel that the complete removal of the inhibitor from the stimulator will be necessary before experiments can be fruitful. DiZerega et al [32,33] have found an aromatase inhibitor present in preovulatory follicular fluid of the pig and human which is about 18.000 daltons. It would be apparent from the present gel exclusion studies that it is not the same as our granulosa cell maturation stimulatory ac tivity in LFF since our activity is about 30,000 daltons.…”

Section: Discussionmentioning

confidence: 99%

Stimulatory Action of Follicular Fluid Components on Maturation of Granulosa Cells from Small Porcine Follicles

Kolena¹,

Channing²

1985

Horm Res

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Follicular fluid obtained from large (6-12 mm) porcine follicles (LFF) was investigated to determine its stimulatory activity on progesterone secretion and on follicle stimulating hormone (FSH) induction of ¹²⁵I-human chorionic gonadotropin (hCG)-luteinizing hormone (LH) binding sites in porcine granulosa cells in a 4-day culture. Incubation of granulosa cells harvested from small porcine follicles (1-2 mm) with 50% LFF led to stimulation of LH/hCG binding sites and progesterone secretion. After partial purification of pooled LFF or proteins precipitated with 90% ethanol on Sephadex G-100 the greatest stimulatory activity was found in the second protein peak eluted from the column. Chromatography of part of the active fraction on DEAE Sephacel using a continuous gradient of NH4HCO₃ yielded seven protein fractions. The second fraction, which eluted early, contained the majority of the stimulatory activity which was purified about 32-fold compared to native LFF. In contrast, addition of follicular fluid recovered from small porcine follicles inhibited FSH induction of LH/hCG binding sites and progesterone secretion. It can be concluded, that maturation of granulosa cells from small follicles may be enhanced by protein(s) present in LFF, but not in fluid recovered from less mature follicles.

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“…FRP is secreted by granulosa cells, in which it inhibits aromatase activity (diZerega et al, 1983(diZerega et al, ,1985. In in vitro studies, it has been shown that FRP is nontoxic to granulosa cells, because its effects are reversible (Schreiber and diZerega, 1986).…”

Section: Introductionmentioning

confidence: 99%

“…Follicular regulatory protein (FRP) isolated from porcine follicular fluid is structurally different from other gonadal proteins and does not directly affect the gonadotropin output of the pituitary (for review see diZerega et al, 1987). FRP is secreted by granulosa cells, in which it inhibits aromatase activity (diZerega et al, 1983(diZerega et al, ,1985. In in vitro studies, it has been shown that FRP is nontoxic to granulosa cells, because its effects are reversible (Schreiber and diZerega, 1986).…”

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confidence: 99%

Quantitative assessment of the biological effects of follicle regulatory protein on dihydrotestosterone‐maintained spermatogenesis in hypophysectomized rat

Ahmad¹,

Toppari²,

diZerega³

et al. 1989

Anat. Rec.

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Follicle regulatory protein (FRP) isolated from porcine ovarian follicles influences folliculogenesis through a paracrine mechanism. A similar protein has been found in the testes and seems to have some inhibitory effects on spermatogenesis when administered to intact male experimental animals. On the basis of female and male studies, it has been ascertained that the effects of FRP are at the level of gonads and not the pituitary or the hypothalamus. In the studies with intact males it was not possible to determine the exact site of FRP action on the testes. Dihydrotestosterone (DHT) has been shown to maintain spermatogenesis in hypophysectomized rats. In order to determine if the inhibitory effects of FRP are at steps prior to the formation of DHT, FRP was administered to hypophysectomized rats that were injected with DHT. Groups of adult rats were hypophysectomized and treated daily with FRP, DHT, FRP + DHT, or vehicle alone for 30 days. At necropsy, body, testes, prostate glands, and seminal vesicle weights were recorded. One testis and sexual accessory glands were fixed for histological evaluation. The contralateral testis was decapsulated, six 2 mm segments of seminiferous tubules, representing defined stages of spermatogenesis, were isolated by transillumination-assisted microdissection, and spermatogenic cells were quantified by DNA flow cytometry. Histologically, the seminiferous tubules of vehicle-treated hypophysectomized controls showed advanced regression. Rats treated with FRP alone showed similar degeneration. On the other hand, rats treated with DHT showed maintenance of spermatogenesis comparable to normal controls. The testes of rats treated with FRP + DHT were indistinguishable from those treated with DHT only. Flow cytometric quantification of germinal cells from all groups confirmed the histological findings. In this study FRP did not exert deleterious effects on DHT-maintained spermatogenesis. This finding suggests that the inhibitory effects of FRP on spermatogenesis in intact animals may not be a direct effect on spermatogenic cells but may impair androgen action or production or DHT formation.

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The Possible Role for a Follicular Protein in the Intraovarian Regulation of Folliculogenesis

Cited by 22 publications

References 46 publications

Inhibition of Placental Aromatase Activity in a Cell Free Assay by Ovarian Protein

Inhibition of Placental Aromatase Activity in a Cell Free Assay by Ovarian Protein

Stimulatory Action of Follicular Fluid Components on Maturation of Granulosa Cells from Small Porcine Follicles

Quantitative assessment of the biological effects of follicle regulatory protein on dihydrotestosterone‐maintained spermatogenesis in hypophysectomized rat

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