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At least 19 recordsLinked to original sources

PubMed1978

Localization and in vitro synthesis of prostaglandins in components of rabbit preovulatory graafian follicles.

Graafian follicles obtained 9 hours after the injection of human chorionic gonadotropin (hCG) into mature rabbits were dissected into a follicular fluid component, a granulosa cell-oocyte component, and a residual wall component, (the latter containing mostly theca tissue with a small and variable amount of adhering granulosa cells). The amounts of PGE and PGF were determined for each component. The follicular fluid contained approximately 4-10 times more PGE and PGF than either the granulosa cell-oocyte component or the residual wall component. The latter two components contained approximately equal amounts of these prostaglandins. The in vitro biosynthesis of PGE and PGF was also studied and it was found that the granulosa cell-oocyte component had about 4 fold the capacity of the residual wall, and that the follicular fluid synthesized no prostaglandins. There was no significant effect of LH on either PGE or PGF synthesis in any of the components.

Animals↗

PubMed1976

Effects of gonadotrophins on the cumulus oophorus of isolated rat Graafian follicles.

Graafian follicles were extirpated before the endogenous LH surge on the day prior to ovulation from PMS-injected immature rats. They were incubated in chemically defined medium in presence or absence of gonadotrophins for 4-10 h. After incubation the oocyte-cumulus complexes were recovered from the follicles and one group inspected by Nomarski interference contrast microscopy and one group was placed in saline containing hyaluronidase. In hormone-free medium both the oocyte and the cumulus cells remained morphologically unchanged: a dictyate oocyte surrounded by a compact mass of cumulus cells. Hyaluronidase did not detach cells from the cumulus structure. However, in presence of LH or FSH morphological changes developed in both cell types: the oocyte resumed meiosis as revealed by germinal vesicle breakdown and polar body formation; the cumulus structure became dispersed and embedded in a viscous matrix. The individual cumulus cells displayed pseudopodia-like processes of the cell surface. Treatment with hyaluronidase resulted in detachment of cells from the cumulus. The effects of LH described on the oocyte and cumulus cells were unimpaired in presence of cyanoketone or aminoglutethimide although these agents blocked the follicular relase of progesterone, estradiol and androstenedione as revealed by RIA. The results indicate that a close functional relationship exists between the two cell types of the cumulus oophorus, the oocyte and the cumulus granulosa cells. Both cell types are affected directly or indirectly by gonadotrophins and characteristical morphological changes develop synchronously in both cell types.

Aminoglutethimide↗

PubMed1975

Progesterone, oestradiol-17 beta and testosterone levels in the follicular fluid of tertiary follicles and Graafian follicles of human ovaries.

Radioimmunoassays of testosterone (T), oestradiol-17 beta (Oe2) and progesterone (P) in the fluid of a total of 47 follicles of different degrees of maturity gave the following mean values: T: 49 ng/ml, Oe2: 932 ng/ml, P: 999 ng/ml. In normal, atretic and cystic tertiary follicles not larger than 1 cm and without luteinized theca interna the following mean values were calculated: T: 54 ng/ml, Oe2: 502 ng/ml, P: 368 ng/ml. In six women mature and less mature follicles were compared, the former having significantly higher Oe2 and higher P values but significantly lower T values than the latter. Genuine Graafian follicles were observed four times, once after HMG stimulation; the values observed lay within the following ranges: T: 12-35 ng/ml, Oe2: 1900-4100 ng/ml, P: 156-6000 ng/ml. The difference in concentration compared with cubital-vein blood before ovulation was highest for Oe2, suggesting a particularly marked aromatinzing activity of the follicles of that phase of the cycle. The findings suggest that in the course of accelerated follicular ripening prior to ovulation both the aromatizing enzyme and 3 beta-hydroxysteroid-dehydrogenase are activated, resulting in a sharper rise in Oe2 and P. The profuse production of P causes a transistory lack of precursors for androgen and oestrogen production (T and Oe2 declines). In the course of an overall increase in steroid production during the luteal phase - which probably goes hand in hand with an increased supply of pregnenolone - there is not only a pronounced rise in progesterone but also a moderate increase in oestrogen production. The androgens are transformed more rapidly into oestrogens on account of the marked activity of the aromatizing enzyme in the corpus luteum and thus show a decline in the luteal phase.

Adult↗

PubMed1977

Stimulation by cyclic nucleotides of prostaglandin E production in isolated graafian follicles.

Rat Graafian follicles isolated intact responded to 8-Br-cyclic AMP and 8-Br-cyclic GMP with increased prostaglandin E (PGE) production during a 6 h incubation. By contrast, 8-Br-cyclic IMP, 8-Br-5' AMP and 8-Br-5' GMP were inactive in this respect. The effect of 8-Br-cyclic AMP and 8-Br-cyclic GMP was noted only after a lag period of about 4 h. Choleragen, LH, and the phosphodiesterase inhibitor (3-isobutyl-l-methyl-xanthine; IBMX) also stimulated PGE production. Actinomycin D and cycloheximide given simultaneously with 8-Br-cyclic AMP or LH prevented the stimulatory effect of these agents. Concomitant addition of arachidonic acid did not overcome the effect of these inhibitors. Administration of hCG in vivo or incubation with LH in vitro did not elevate endogenous ovarian free arachidonate, while PGE production was enhanced. Dexamethasone prevented this stimulatory effect of hCG. Collectively, the results suggest that stimulation of ovarian PGE production by cyclic nucleotides and LH is dependent on de novo synthesis of one or more components of the PG synthetase system rather than on substrate availability. Cyclic nucleotides may mediate the stimulatory effect of gonadotropins on PGE production.

Adenosine Monophosphate↗

PubMed1994

Development of luteinized graafian follicles in patients with karyotypically normal spontaneous premature ovarian failure.

Despite having amenorrhea and markedly elevated serum gonadotropin levels, some women with karyotypically normal spontaneous premature ovarian failure, nevertheless, have ovarian follicles that function intermittently. Graafian follicles capable of responding to these high FSH levels are faced with high serum LH levels as well, which might induce inappropriate luteinization and prevent normal follicle function. We examined this possibility using weekly blood sampling and sonography in 65 patients. Nearly 50% of our patients demonstrated ovarian follicle function [serum estradiol, > 183 pmol/L (50 pg/mL)] during a median of 4 months of observation (range, 2-6 months). However, during this observation, only 16% achieved an ovulatory serum progesterone level [> 9.5 nmol/L (3.0 ng/mL)]. We imaged an antral follicle by sonography in over 40% of patients (27 of 65), and serum estradiol was significantly greater when an antral follicle was present. The follicles in these patients were not functioning normally, however. In contrast to normal women, patients with ovarian failure had poor correlation between follicle diameter and serum estradiol. We biopsied these antral follicles in 6 patients and found luteinized Graafian follicles in all cases. Therefore, luteinized Graafian follicles account for at least 60% of the antral structures imaged (95% confidence limit). Thus, inappropriate luteinization of Graafian follicles appears to be a major pathophysiological mechanism in patients with karyotypically normal spontaneous premature ovarian failure.

Adult↗

PubMed1969

Luteinizing hormone: action on the graafian follicle in vitro.

Graafian follicles, dissected intact from the rabbit ovary and incubated for 40 minutes with luteinizing hormone, developed into corpora lutea when autotransplanted under the kidney capsule. Follicles incubated with follicle-stimulating hormone or without hormone degenerated and failed to luteinize. Direct exposure of the mammalian follicle to luteinizing hormone initiates luteinization and formation of the corpus luteum.

Animals↗

PubMed1983

Graafian follicle growth and replacement in anovulatory ovaries of ageing C57BL/6J mice.

The growth of preantral follicles and replacement of large Graafian follicles was studied in reproductively senescent C57BL/6J mice immediately after the loss of oestrous cyclicity when the ovary is approaching exhaustion of its follicular reserve. Granulosa cells were labelled in vivo by injection of tritiated thymidine and were evaluated by autoradiography. At 1 h after injection, labelling was confined almost exclusively to the cumulus and neighbouring cells whereas the distribution of labelled granulosa cells in preantral follicles was approximately uniform. The proportion of labelled mural cells in Graafian follicles rose from initially low values to maximal levels 3 days later; this suggested that those follicles that were Graafian at the time of injection had been replaced by recruitment of preantral stages. The rate of growth of preantral follicles was similar in senescent anovulatory mice and in young adult animals. A simple model was constructed to illustrate how persistent vaginal cornification in ageing mice is sustained by a stream of Graafian follicles and why some of the latter did not respond fully to an ovulatory dose of hCG.

Aging↗

PubMed1975

The distribution of delta5-3beta-hydroxysteroid dehydrogenase in the graafian follicle of the mare.

Graafian follicles of various sizes obtained from mares at different stages of the oestrous cycle were examined histologically and histochemically for delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity and related enzymes. The 3beta-HSD activity was not found in the theca interna of any follicles but was present in the membrana granulosa of well-vascularized large follicles in the late luteal phase of the cycle and at oestrus. These findings indicate that pregnenolone cannot be converted into progesterone in the theca interna. It is suggested that this conversion occurs in the membrana granulosa and that progesterone then passes into the theca interna where it is converted into oestrogen. Participation of both granulosa and thecal cells in oestrogen production is also discussed from a morphological view-point.

Animals↗

PubMed1976

Hormone-stimulated desensitization of hormone-dependent adenylyl cyclase. Dual action of luteninizing hormone on pig graafian follicle membranes.

Washed membrane particles from pig Graafian follicles larger than 6 mm in diameter were found to contain an adenylyl cyclase system that is highly responsive to luteinizing hormone (LH). Under the assay conditions used (1.5 mM ATP, 5 mM MgCl2, 1.4 mM EDTA, and 1.0 mM ethylene glycol bis(beta-aminoethyl)-N,N'-tetraacetic acid, pH 7.0) LH stimulated enzyme activity up to 7-fold. Half-maximal activation was obtained between 3 and 6 X 10(-10) M of added LH, provided the reaction was carried out under equilibrium conditions. In contrast to findings in large follicles, adenylyl cyclase activity was found to be unresponsive to LH in small immature follicles (1 to 2 mm in diameter) and partially responsive to LH (2- to 3-fold stimulation over basal) in follicles of medium size (3 to 5 mm in diameter). Washed membrane particles from follicles larger than 6 mm were found to contain also an ATP- and Mg2+-dependent process which, upon incubation at 30 degrees, causes the adenylyl cyclase system to lose its susceptibility to respond to LH. Because this loss of LH-stimulated activity was not accompanied by a concomitant loss of basal activity, it was concluded to be the expression of a desensitization reaction. Desensitization was almost undetectable at 5 mM total added MgCl2 and required, to be readily detectable, addition of MgCl2 concentrations in excess of 10 mM. LH was found to stimulate desensitization in the presence of 1 mM cyclic adenosine 3':5'-monophosphate by diminishing the requirement for MgCl2. Loss of LH-stimulated adenylyl cyclase activity was readily detectable at 5.0 mM total added MgCl2 in the presence of 10 mug per ml of LH. Half-maximal stimulation of desensitization by LH was found to occur at about 25 X 10(-10) M, i.e. at about 4 to 6 times higher concentrations than needed for half-maximal stimulation of adenylyl cyclase activity. Half-maximal LH-stimulated desensitization was obtained with 0.5 to 0.7 mM ATP in the incubation. Neither GTP, nor adenyl-5'-yl imidodiphosphate, the nonphosphorylating imidodiphosphate analogue of ATP, supported the desensitization reaction, suggesting that this process may be mediated via phosphorylation of one or more of the components of the adenylyl cyclase system. LH-stimulated desensitization was detected also in washed membrane particles derived from dissected rabbit Graafian follicles, whose adenylyl cyclase becomes desensitized in vivo within minutes after human chorionic gonadotropin injection (Hunzicker-Dunn, M., and Birnbaumer, L., Endocrinology, in press), but not in membrane particles from corpora lutea of pregnant or pseudopregnant rabbits, whose adenylyl cyclase becomes desensitized in vivo only several hours or days after human chorionic gonadotropin injection (Hunzicker-Dunn, M., and Birnbaumer, L., Endocrinology, in press). It is suggested that both actions of LH (stimulation of adenylyl cyclase and stimulation of desensitization) are receptor-mediated, and that neither of them is mediated by cyclic adenosine 3':5'-monophosphate...

Adenosine Triphosphate↗

PubMed1982

Norepinephrine in Graafian follicles is depleted by follicle-stimulating hormone.

The purpose of the present study was to measure norepinephrine (NE) in Graafian follicles and correlate changes in its concentration with circulating gonadotropins secreted endogenously or administered exogenously. Graafian follicles were removed from the ovaries of adult cycling rats. The follicles were pooled in groups of 10-13, and NE was determined by high performance liquid chromatography. Follicular NE(picograms per micrograms protein) did not change between 0900 h (3.61 +/- 0.34) and 1300 h (3.12 +/- 0.25) on proestrus, but was reduced significantly to 1.45 +/- 0.16 at 2100 h, which is 4 h after the peak of the gonadotropin surge. There was a further reduction to 0.83 +/- 0.08 in fresh corpora lutea taken on estrus at 0900 h. The decrease in follicular NE was prevented in estrous rats which were either hypophysectomized 24 h previously or treated with sodium pentobarbital at 1330 h on proestrus. To determine which pituitary hormone was responsible for follicular NE depletion, rats were injected at 0900 h on proestrus with LH (5 micrograms), FSH (20 micrograms), LH plus FSH (5 and 20 micrograms, respectively), or PRL (20 micrograms), and follicular NE was determined 4 h later. FSH reduced follicular NE significantly to 1.86 +/- 0.16 compared to both the control (3.12 +/- 0.25) and the PRL-injected group (2.92 +/- 0.32), whereas LH caused a small but nonsignificant decrease (2.49 +/- 0.2). Both LH and FSH doses used resulted in ovulation, as determined by counting tubal ova 12 h after hormonal treatment. We conclude that 1) NE in Graafian follicles is markedly reduced within 4 h after the preovulatory gonadotropin surge in the normal cycling rat; this reduction is prevented when the surge is abolished; 2) the hormone responsible for follicular NE depletion is FSH rather than LH or PRL; and 3) finally, it is suggested that follicular NE may be involved with the formation and/or functioning of the corpus luteum.

Animals↗

PubMed1979

Relationship between steroidogenesis and oocyte maturation in rat graafian follicles cultured in vitro.

Rat Graafian follicles were dissected from ovaries during the morning of proestrus and incubated in various media. After an 8 h incubation period, ovarian follicles were collected and analyzed, by radioimmunoassay, for progesterone, 17 alpha-hydroxyprogesterone, androstenedione, estradiol-17 beta, and dihydrotestosterone. Following incubation in proestrus (a.m.) serum, preovulatory follicles secreted all these steroids and the output of progesterone, 17 alpha-hydroxyprogesterone and androstenedione was markedly stimulated following the addition of LH to the media. Follicle-enclosed oocytes resumed meiosis when incubated in proestrus serum without added LH. However, germinal vesicle break-down (GVBD) under these conditions was considerably slower than that observed following addition of LH to the medium. "Spontaneous" maturation of oocytes in proestrus serum was associated with increased production of steroids. Oocyte maturation and steroidogenesis both occurred following incubation of ovarian follicles in serum obtained from hypophysectomized rats. Addition of LH to the media markedly accelerated these responses. These results suggest that oocyte maturation and steroidogenesis also occur in cultured ovarian follicles in the absence of gonadotrophic hormones. The relationship between steroidogenesis and/or spontaneous oocyte maturation are discussed.

Androstenedione↗

PubMed1997

Graafian follicles are cooler than neighbouring ovarian tissues and deep rectal temperatures.

In order to establish appropriate culture temperatures for in-vitro maturation of pig ovarian oocytes, large Graafian follicles (7-10 mm diameter) were sensed by infra-red technology during the latter part of a spontaneous oestrous cycle. Temperatures were measured under systemic anaesthesia almost instantaneously upon revealing the ovaries at mid-ventral laparotomy. Temperature differentials were observed within all 16 ovaries sensed in 14 animals. Ovaries were always cooler than deep rectal temperatures (mean rectal temperature was 38.0 +/- 0.4 degrees C; range 37.5-38.6 degrees C) and mature follicles always cooler than ovarian stroma (35.6 +/- 0.3 degrees C versus 37.3 +/- 0.2 degrees C respectively; P < 0.01). Such follicles were frequently 1.5-1.8 degrees C cooler than the adjacent stroma, the mean being 1.7 +/- 0.4 degrees C. Small Graafian follicles (< 5-6 mm diameter) and recent ovulations did not show this differential. The control experiment of excising an ovary, deep freezing it in liquid nitrogen, and then restoring it to the body cavity before further sensing indicated that intra-ovarian temperature gradients depended on the activity of living tissues and/or a functional blood supply. Furthermore, calculation of anticipated rates of cooling for exposed Graafian follicles strongly suggested that artefacts could not have been solely responsible for the observed temperatures. Endothermic reactions within mature follicles were thus brought into focus. It is concluded that follicular temperatures may influence the meiotic progression and cytoplasmic maturation of oocytes and act to regulate enzymatic activity in the biosynthetic pathways for steroid and/or peptide hormones.

Animals↗

PubMed1994

An immunohistochemical study of the vascularization of the human Graafian follicle.

The wall of the largest Graafian follicle or corpus luteum was biopsied in 22 patients at laparoscopy. Both granulosa and theca cells were contained in 18 samples. These samples were classified as pre-luteinizing hormone (LH) surge (n = 3), LH surge (n = 3), early luteal (n = 3), mid-luteal (n = 4), late luteal (n = 3) and menstrual (n = 2). A double-staining immunohistochemical protocol was used to demonstrate proliferating endothelial cells: mouse-anti-rat-proliferating cell nuclear antigen, for proliferating cells; mouse-anti-human-CD34 antibody for endothelial cells. The percentage of endothelial cells proliferating (proliferation index) and the area of tissue occupied by endothelial cells (areal fraction) were determined for granulosa and theca layers. Intra- and inter-slide coefficients of variation were < 15%. The granulosa layer was avascular until the LH surge subsided. Maximum vascularization was achieved by the mid-luteal phase. The theca endothelial cell proliferation index was constant from pre-LH surge to mid-luteal phases. The mean theca endothelial cell proliferation index for these phases was significantly greater than for the late luteal and menstrual phases. From first appearance in the granulosa layer, endothelial cells had the same proliferation index as the theca endothelial cells, the proliferation index decreasing significantly in both after the mid-luteal phase (P = 0.018). It is concluded that endothelial cell proliferation is unchanged throughout the follicular, early and mid-luteal phases, decreasing significantly in the late luteal phase. By contrast, endothelial cell invasion of the membrane granulosa, presumably in response to a chemotactic stimulus, occurs after the LH surge has subsided.

Antigens, CD↗

PubMed1978

Oestradiol production by human graafian follicles cultured in vitro.

Intact human Graafian follicles recovered during the preovulatory phase of the menstrual cycle and cultured in vitro, gave a mean oestradiol production of 33 ng/hour over periods of 4 to 92 hours. Treatment of follicles with human pituitary gonadotrophin or human chorionic gonadotrophin resulted in an increased production of oestradiol.

Adult↗

PubMed1986

LHRH stimulates plasminogen activator and inhibits steroid production by granulosa cells of adult rat Graafian follicles.

We studied the effects of LHRH and its analogs on plasminogen activator production and progesterone and estradiol secretion by granulosa cells isolated from adult rat Graafian follicles. LHRH and its agonist ([des- -Gly10,D-Trp6,Pro9-NHEt]LHRH) stimulated small but significant increases in plasminogen activator production. This stimulatory action of LHRH was blocked by the addition of the specific antagonist ([D- pGlu1,D-Phe2,D-Trp3,6]LHRH). In contrast, LHRH treatment had no significant effect on basal steroid production by granulosa cells of Graafian follicles cultured for 2-6 days. However, LHRH decreased the FSH-stimulated steroidogenesis. This inhibitory effect of LHRH on steroidogenesis was abolished by concomitant addition of the LHRH antagonist. The results show that LHRH has a stimulatory effect on plasminogen activator production and a suppressive action on steroidogenesis in granulosa cells isolated from Graafian follicles of adult rats.

Animals↗

PubMed1991

Developmental regulation of heat-shock response in mouse oogenesis: identification of differentially responsive oocyte classes during Graafian follicle development.

The response to heat (hs response) of dictyate mouse oocytes at various differentiation stages was analyzed in vitro, by determining patterns of oocyte heat-shock (hs) gene expression and heat-shock protein (HSP) synthesis, under both normal conditions and after an hs. Growing oocytes constitutively synthesized HSP89 and HSC70, and, in contrast to preovulatory oocytes which do not display an hs response, displayed a heat-elicited, transcription-dependent synthesis of two HSP68 isoforms, but not of other inducible HSPs. To determine the developmental schedule of hs response disappearance during oogenesis, fully grown oocytes from Graafian follicles were morphologically sorted into three discrete classes related to the follicle development, namely, loosely associated with granulosa cells (LA oocytes, from small Graafian follicles), intermediately associated with granulosa cells (IA oocytes, from medium-sized Graafian follicles), and cumulus-associated (CA oocytes, from mature follicles). LA oocytes displayed an hs response qualitatively similar to, but smaller in extent than, that of growing oocytes, and were able to resume and complete spontaneous meiotic maturation in vitro at a high rate after hs. We conclude that hs response of mouse dictyate oocytes is maximal during growth period, significantly declines with acquisition of full oocyte size and antrum formation within the follicle, and is finally shut off with oocyte/follicle terminal differentiation.

Animals↗

PubMed1976

The role of prostaglandins in the development of refractoriness to LH stimulation by Graafian follicles.

The possibility that prostaglandins might be responsible for the development of the pre-ovulatory refractoriness to the stimulation by LH of cyclic AMP accumulation in vitro in the Graafian follicle was examined. Isolated rabbit Graafian follicles were obtained at estrus and at 0.5, 5 and 9 hours after an ovulatory dose of LH. The follicles were incubated in vitro in the presence of (8-3H)adenine and the accumulation of (8-3H)cyclic AMP measured. Follicles from estrous animals responded to the in vitro addition of LH with a marked increase of cyclic AMP accumulation and lost this response as the time of ovulation approached. Animals pretreated with indomethacin, which inhibits the usual pre-ovulatory rise of follicular prostaglandin levels, showed essentially the same loss of responsiveness. Indomethacin alone was without effect. It is concluded that prostaglandins are not the major factor in the development of refractoriness to LH stimulation in vitro which has been observed in pre-ovulatory follicles.

Animals↗

PubMed1975

Functional and structural relationships in the Graafian follicle population of the sheep ovary.

The Graafian follicle population in sheep can be divided into two groups on the basis of the capacity that individual follicle have for secreting oestrogen when isolated from the remainder of the ovary (Moor, 1973). The most developed one or two non-atretic follicle from each animal generally produce large amounts of oestrogen in culture and can thus be classified as steroidogenically 'activated'. The other follicles usually produce very little oestrogen in culture and are accordingly classified as 'non-activated'. In this paper the above classification will be used and the two groups of follicles will be considered separately. In the first section of the paper the response of the non-activated follicles to gonadotrophic stimuli will be described and related to growth and atresia within this population. The steroidogenic potential of the activated follicles at different stages of the cycle will be discussed in the second part of the paper. In the third part, an attempt will be made to relate the ultrastructure of the activated follicles to the functional activity of their component tissues, namely the theca interna and membrana granulosa.

Androstenedione↗