Effects of FSH and LH on incorporation of [3H]thymidine into follicular DNA

Roy, Shyamal K.; Greenwald, Gilbert S.

doi:10.1530/jrf.0.0780201

Cited by 33 publications

(22 citation statements)

References 8 publications

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“…There is evidence from other studies that FSH is involved in compensatory maturation of antral follicles in rats (Hirshfield, 1982), and in other species it has been shown to increase DNA synthesis by granulosa cells in cultured preantral follicles (Ryle, 1972;Roy & Greenwald, 1986 The relationship between the fraction of the total follicle population removed and the fraction of potential oestrous cycles lost is not a simple proportion. Halving follicle numbers resulted in the loss of only a quarter of expected cycles.…”

Section: Ovarian Cycle Historymentioning

confidence: 99%

Ovarian cyclicity and follicular recruitment in unilaterally ovariectomized mice

Gosden

Telfer²,

Faddy³

et al. 1989

Reproduction

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Summary. Halving the numbers of follicles in young adult mice by unilateral ovariectomy resulted in compensatory Graafian follicle growth with a reduction by about 25% of the expected number of oestrous cycles. The impact of the operation on the numbers and dynamics of preantral follicles during the first 2 months after ovariectomy was studied using a compartmental mathematical model to analyse differential follicle counts. There were changes in growth and/or death rates at all stages of follicle development, and the patterns emerging were time-dependent. The rate of follicle survival from the pool of unilaminar stages was paradoxically reduced, but those forming two granulosa cell layers continued to develop towards Graafian size. As the frequency of follicle death declined, the numbers of healthy large preantral and antral stages in unpaired ovaries rose to approach those in pairs of age-matched control ovaries, suggesting that follicles otherwise undergoing atresia were being rescued. In the long-term, follicle dynamics after unilateral ovariectomy at young ages did not appear to compromise fecundity seriously.

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Section: Ovarian Cycle Historymentioning

confidence: 99%

Ovarian cyclicity and follicular recruitment in unilaterally ovariectomized mice

Gosden

Telfer²,

Faddy³

et al. 1989

Reproduction

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“…Serum levels of gonadotropins were determined by specific RIAs using rat-rat RIA kits from the National Pituitary Hormone Program as described previously [23,25,29]. All samples were assayed at the same time to avoid any interassay variation.…”

Section: Measurements Of Serum Fsh and Lhmentioning

confidence: 99%

“…4). In the hamster [23,25,31], serum levels of LH started increasing by 1400 h on Day 4, reaching a peak at 1600 h. The FSH surge occurs at 1500 h on Day 4, reaching a peak at 1600 h. Coinciding with the increase in serum levels of FSH and LH, ovarian FSHR mRNA levels decreased noticeably by 1600 h on Day 4 (Fig. 4), and these levels declined further by 2000 h to reach the levels of 0900 h at Day 1 (Fig.…”

Section: Ovarian Fshr Mrna Levels Throughout the Estrous Cyclementioning

confidence: 99%

“…To determine whether the decline in ovarian FSHR mRNA levels in the hamster was really induced by the preovulatory gonadotropin surge, hamsters were injected with phenobarbitone at 1300 h to block the surge [25,28], and the steady-state levels of ovarian FSHR mRNA were examined at 2000 h on Day 4 and at 0900 h on Day 1. Serum levels of LH and FSH increased significantly by 1600 h on day 4, which was completely blocked by phenobarbitone pretreatment (data not shown) [22,25].…”

Section: Effect Of Endogenous Fsh Surge On Ovarian Fshr Mrna Levelsmentioning

confidence: 99%

“…Because FSH plays very important roles during hamster follicular development [1,13], it will be important to know if FSH, whether endogenous or exogenous, influences ovarian FSHR mRNA levels. This information will be particularly relevant to understanding how preantral follicles grow after the preovulatory gonadotropin surge [24,25]. The objectives of the present study were to identify the complete cDNA sequence of the hamster FSHR, to determine the steady-state levels of FSHR mRNA in the ovary during the estrous cycle, and to evaluate the effects of endogenous and exogenous FSH on FSHR mRNA levels.…”

Section: Introductionmentioning

confidence: 99%

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Downregulation of Follicle-Stimulating Hormone (FSH)-Receptor Messenger RNA Levels in the Hamster Ovary: Effect of the Endogenous and Exogenous FSH1

Zhang

Roy

2004

Biology of Reproduction

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Although gonadotropins have been reported to downregulate FSH-receptor (FSHR) mRNA levels in the ovaries of female rats, the effect of the gonadotropin surge, particularly FSH, on hamster follicular FSHR mRNA levels warrants further examination. The objectives of the present study were to clone and determine the complete FSHR cDNA sequence of the hamster and to delineate the effects of endogenous and exogenous FSH on the steady-state levels of ovarian FSHR mRNA. Complete FSHR cDNA was derived from hamster ovarian total RNA by the strategy of 3'- and 5'-rapid amplification of cDNA ends. Ovaries were obtained before and after the endogenous gonadotropin surge or exogenous FSH administration, and the steady-state levels of FSHR mRNA were assessed by Northern blot hybridization. Cloned FSHR cDNA consists of a reading frame corresponding to exons 1-10 of the human FSHR gene and the 5'- and 3'-untranslated regions. The nucleic acid and amino acid sequences of the reading frame were at least 87% and 92% identical, respectively, to that of human, rat, and mouse FSHR. Furthermore, the amino acid sequence contained seven transmembrane domains characteristic of the FSHR. The steady-state levels of FSHR mRNA increased from estrus (Day 1) to reach a peak on proestrus (Day 4) noon; however, significant attenuation was noted following the gonadotropin surge, which was blocked by phenobarbital. Exogenous FSH also downregulated, both dose- and time-dependently, ovarian FSHR mRNA levels. These data indicate that the nucleic acid sequence of hamster FSHR has been identified and that FSH modulates FSHR mRNA levels in the hamster ovary.

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Regulation of DNA synthesis in goldfish vitellogenic ovarian follicles by hormones and growth factors

Srivastava

Kraak

1994

J. Exp. Zool.

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The present study examines the effects of selected hormones and growth factors on deoxyribonucleic acid (DNA) synthesis by goldfish vitellogenic and prematurational full-grown ovarian follicles in vitro. The synthesis of DNA was assessed from the incorporation of [3H]-thymidine after preincubation in medium supplemented with fetal bovine serum, followed by a second incubation in serum-free medium with several combinations of hormones and growth factors. DNA synthesis by vitellogenic ovarian follicles was enhanced by the addition of ovine and porcine insulin (0.440 pg/ml) and human recombinant insulin-like growth factor I (IGF-I, 12.5-100 ng/ml) and IGF-I1 (50-100 ng/ml); the order of potency was IGF-I > IGF-I1 > insulin. The interactive effects of insulin, IGF-I, and IGF-I1 on DNA synthesis by vitellogenic follicles were additive, suggesting that these peptides may act through distinct receptors. By comparison, both insulin (4 pg/ ml) and IGF-I (100 ng/ml) had no effect on DNA synthesis by prematurational full-grown follicles, suggesting that sensitivity of ovarian follicles to insulin and IGF-I may change during follicular development. IGF-I (25-200 ng/ml) and IGF-I1 (25-200 ng/ml) had no effect on basal and human chorionic gonadotropin (hCG)-stimulated testosterone and 17P-estradiol production by vitellogenic follicles, suggesting that these growth factors may play a role in regulating follicular DNA synthesis but not ovarian steroidogenesis. Carp gonadotropins (cGtH-I and cGtH-II), hCG, and 178estradiol also enhanced DNA synthesis by vitellogenic follicles. The effects of hCG and 17P-estradiol on DNA synthesis were further enhanced in the presence of either insulin or IGF-I. In conclusion, these data provide convincing evidence of the mitogenic actions of insulin, IGFs, gonadotropins, and 17P-estradiol, suggesting that these hormones and growth factors may regulate follicular growth and development in the goldfish.

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Effects of FSH and LH on incorporation of [3H]thymidine into follicular DNA

Cited by 33 publications

References 8 publications

Ovarian cyclicity and follicular recruitment in unilaterally ovariectomized mice

Ovarian cyclicity and follicular recruitment in unilaterally ovariectomized mice

Downregulation of Follicle-Stimulating Hormone (FSH)-Receptor Messenger RNA Levels in the Hamster Ovary: Effect of the Endogenous and Exogenous FSH1

Regulation of DNA synthesis in goldfish vitellogenic ovarian follicles by hormones and growth factors

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