SEARCH · PubMed Health

Results for “Luteinization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources

PubMed1992

Localization of oestrogen receptors in preoptic neurons containing neurotensin but not tyrosine hydroxylase, cholecystokinin or luteinizing hormone-releasing hormone in the male and female rat.

The neurochemical identity of preoptic neurons containing oestrogen receptors was investigated in the male and female rat using a sequential double-staining immunocytochemistry procedure. Single-immunostaining revealed large populations of cells with nuclear immunoreactivity to the oestrogen receptor in the medial preoptic area of the male and female rat. Optimal double-staining of sections for the oestrogen receptor and one of several neuropeptides or tyrosine hydroxylase, was achieved with short-term (two- to four-day) gonadectomized rats treated with colchicine where necessary. Neurotensin-immunoreactive cells were distributed in a sexually dimorphic manner in the region of the anteroventral preoptic nucleus and exhibited oestrogen receptor immunoreactivity in both sexes. Double-labelled cells in this area of the female rat comprised 50% and 11% of the total neurotensin- and oestrogen receptor-containing cell populations, respectively, compared with 25% and 4% in the male (P less than 0.01). The numbers of neurotensin-immunoreactive cells in the region of the medial preoptic nucleus were similar in male and female rats with double-labelled cells making up 20-38% and 3-5% of the total numbers of cells containing neurotensin and oestrogen receptors, respectively, in both sexes. Neurons immunoreactive for tyrosine hydroxylase were distributed in a gender-specific manner within the anterior periventricular area but were not immunoreactive for the oestrogen receptor in either sex. Following colchicine treatment, cholecystokinin-immunoreactive cells were identified predominantly within periventricular regions of the preoptic area and similarly, did not possess immunoreactivity to the oestrogen receptor in either the male or the female rat. Neurons containing luteinizing hormone-releasing hormone were found immediately lateral to the cell populations containing oestrogen receptors and immunoreactivity to the oestrogen receptor was not identified within any neurons containing luteinizing hormone-releasing hormone in either the male or female rat. The absence of oestrogen receptor immunoreactivity in neurons containing tyrosine hydroxylase, cholecystokinin or luteinizing hormone-releasing hormone suggests that gonadal steroids acting through this receptor do not influence these cells directly in either sex. In particular, it appears that gender-specific patterns of luteinizing hormone secretion cannot be attributed to sex differences in oestrogen receptor localization within luteinizing hormone-releasing hormone neurons. These experiments also show that the sexually dimorphic neurotensin neurons in the preoptic area possess oestrogen receptors and that female rats have larger number of neurons co-localizing neurotensin and oestrogen receptors. As such, these neurons may be involved in mediating sex-specific actions of the gonadal steroids in the preoptic area.

Animals↗

PubMed2005

Expression of steroid receptors, their cofactors, and aromatase in human luteinized granulosa cells after controlled ovarian hyperstimulation.

OBJECTIVE: To examine expression of androgen receptor (AR), AR cofactors, estrogen (E) receptor alpha, E receptor beta, progesterone receptor, steroid receptor coactivator-1, and aromatase in human luteinized granulosa cells collected during oocyte retrieval. DESIGN: Prospective real-time reverse transcriptase-polymerase chain reaction study. SETTING: Academic medical center. PATIENT(S): A total of 198 samples were brought into the study. INTERVENTION(S): Patients underwent the long protocol for assisted reproductive technology. Luteinized granulosa cells were collected transvaginally with ultrasound guidance. Quantitative reverse transcriptase-polymerase chain reaction was performed to quantify the mRNA expression of the investigated genes. MAIN OUTCOME MEASURE(S): The expression levels were determined as ratios between the studied genes and the reference gene beta-actin. RESULT(S): There is little AR expression in human luteinized granulosa cells immediately preceding ovulation under controlled ovarian hyperstimulation. All aspirated follicles, despite their antral size, displayed a similar mRNA expression of the investigated genes in the luteinized granulosa cells. CONCLUSION(S): This study supports the possibility of a transition of androgen action from being an enhancer of follicular differentiation (through the AR) to being a substrate of E synthesis (through aromatase) at the time of oocyte retrieval. The present study also demonstrates no effect of follicular size upon the status of steroid receptor mRNA expression in the luteinized granulosa cells when follicles were at least >1.5 mL.

Aromatase↗

PubMed1998

Premature luteinization: could it be an early manifestation of low ovarian reserve?

OBJECTIVE: To gain insight into the physiologic significance of premature luteinization and to evaluate whether it could be a manifestation of low ovarian reserve. DESIGN: Retrospective evaluation. SETTING: Reproductive medicine unit. PATIENT(S): Thirty-one consecutively seen women with normal ovulation and unexplained infertility. INTERVENTION(S): Induction of superovulation with hMG coupled with synchronized IUI. A GnRH agonist was not used during the study. MAIN OUTCOME MEASURE(S): Premature luteinization was defined as a progesterone/estradiol ratio of > 1 on the day of hCG administration. Patients were evaluated during their first cycles of hMG treatment and then were divided into those with (study group) and those without (control group) premature luteinization. The ovarian reserve parameters were compared between the two groups. RESULT(S): Nineteen of the 31 patients with unexplained infertility demonstrated premature luteinization. Patient characteristics were similar between the study and control groups. Mean (+/- SD) day 3 FSH levels were 8.2 +/- 3.3 and 6.6 +/- 1.7 mIU/mL in the study and control groups, respectively. Mean (+/- SD) day 3 estradiol levels were significantly higher in the study than in the control group (74 +/- 49 pg/mL vs. 30 +/- 17 pg/mL, respectively). Mean (+/- SD) estradiol levels on the day of hCG administration also differed significantly between the study and control groups (760 +/- 539 pg/mL vs. 1,568 +/- 675 pg/mL, respectively). Likewise, the number of follicles that were > or = 15 mm on the day of hCG administration was significantly lower in the study than in the control group (2.9 +/- 1.5 vs. 4.3 +/- 1.3, respectively). The total dose of hMG and duration of administration were similar in the two groups. The clinical pregnancy rates after four cycles of treatment were 15.8% and 41.7% in the study and control groups, respectively. CONCLUSION(S): This preliminary work suggests that, in cycles that are not treated with a GnRH agonist, signs of premature luteinization in patients with unexplained infertility could be an early manifestation of low ovarian reserve. It appears that hMG treatment in this group of patients could uncover the pathogenesis of their infertility.

Adult↗

PubMed1998

Apoptotic cell death in human granulosa-lutein cells: a possible indicator of in vitro fertilization outcome.

OBJECTIVE: To determine whether women who do not conceive during an IVF treatment despite normal FSH levels have a higher rate of apoptosis in their granulosa-lutein cells than women who do conceive. DESIGN: Prospective. SETTING: Large teaching hospital and fertility center. PATIENT(S): Patients with normal FSH levels undergoing an IVF treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Outcome of the IVF treatment and percentage of apoptotic granulosa-lutein cells. RESULT(S): A significantly lower percentage of granulosa-lutein cells were apoptotic in patients who became pregnant compared with those who did not become pregnant. A higher basal FSH level was significantly correlated with the duration of the stimulation, and the number of follicles was significantly inversely correlated with the number of ampules of FSH used and the duration of the treatment. The number of embryos was significantly correlated with the number of oocytes, and significantly inversely correlated with the number of apoptotic granulosa-lutein cells. CONCLUSION(S): Fewer granulosa-lutein cells are apoptotic in women who have an ongoing pregnancy after IVF treatment than in women who do not conceive.

Adult↗

PubMed2000

Preferred treatment of infertile women older than 37 years of age who demonstrate premature luteinization in the first evaluation cycle.

OBJECTIVE: To evaluate the efficacy of various treatments in abolishing premature luteinization in infertile women over 37 years old who are undergoing ovulation induction. DESIGN: Prospective, nonrandomized study. SETTING: Tertiary care medical clinic. PATIENT(S): Seventeen infertile women >37 years old in whom premature luteinization was detected during their evaluation (pretreatment) cycle. INTERVENTION(S): The patients underwent three consecutive treatment cycles with clomiphene citrate (group A), hMG (group B), and a GnRH agonist plus hMG (group C). MAIN OUTCOME MEASURE(S): Premature luteinization, defined as a progesterone/E2 ratio of >1 on the day of hCG administration. RESULT(S): Fifteen (88%) of the 17 patients in group A and 13 (76%) of the 17 patients in group B demonstrated premature luteinization. In contrast, only 1 (6%) of the 17 patients in group C had a progesterone/E2 ratio of >1 on the day of hCG administration. The mean (+/-SD) E2 level on the day of hCG administration was significantly higher in group C (1.236 +/- 772.7 pg/mL) than in group A (214.02 +/- 104.46 pg/mL) or group B (412.5 +/- 337 pg/mL). CONCLUSION(S): Pituitary desensitization with a GnRH agonist in conjunction with hMG may be of benefit for older infertile women who demonstrate early luteinization in their first evaluation cycle.

Adult↗

PubMed2001

Sex steroids modulate luteinizing hormone-releasing hormone secretion in a cholinergic cell line from the basal forebrain.

The function of a particular neuronal population is in part determined by its neurotransmitter phenotype. We have found that a neuronal-derived septal cell line (SN56), known for its cholinergic properties, also synthesizes and releases luteinizing hormone-releasing hormone. In addition, these cells express the messenger RNAs encoding estrogen and progesterone receptors. The activation of these receptors by their respective ligands cooperatively modulates the depolarization-induced release of luteinizing hormone-releasing hormone in these cells. We have also found that a number of septal neurons in postnatal (1-week-old) mice are immunoreactive to both choline acetyltransferase and luteinizing hormone-releasing hormone. These results indicate that both neurotransmitters, acetylcholine and luteinizing hormone-releasing hormone, may co-exist in septal neurons of the CNS and that they could be modulated by gonadal hormones, and suggest that luteinizing hormone-releasing hormone could be involved in some of the actions of sex steroids on cholinergic neurotransmission.

Animals↗

PubMed2002

Differences in steroidogenic acute regulatory protein expression from the luteinizing-granulosa cells of patients undergoing in vitro fertilization with embryo transfer: implications for cycle outcomes.

OBJECTIVE: Previous research has suggested a correlation between the subtle rise in progesterone induced by the administration of human chorionic gonadotropin (hCG) and cycle outcome in patients undergoing in vitro fertilization with embryo transfer (IVF-ET). The data suggest that patients who have <2-fold increase in progesterone levels will not conceive as a result of that IVF-ET attempt (poor responders). Further, if the luteinizing-granulosa cells of poor responders are placed in culture, their steroid hormone production will be significantly less than that of the luteinizing-granulosa cells of patients with a normal response to hCG (>3-fold; normal responders). Recent studies have demonstrated that steroidogenic acute regulatory protein (StAR) regulates the rate-limiting step in steroid hormone biosynthesis. The objective of the present study was to determine whether StAR expression differed in normal responders and poor responders undergoing IVF-ET. STUDY DESIGN: The luteinizing-granulosa cells of 6 patients were isolated after follicular aspiration and assayed for StAR expression. Three sets of cells were from patients exhibiting a normal response to hCG administration and 3 sets were from patients exhibiting a poor response. RESULTS: Data suggest a 17% drop in StAR protein in patients with a poor response to hCG administration when compared with those with a normal response. CONCLUSIONS: Although StAR protein was expressed in all 6 cellular extracts, expression appeared greatest in cells recovered from normal responders. Further, although two thirds of the patients with a normal response reported term pregnancies, no pregnancies were reported in the poor responders. Low levels of progesterone and absence of pregnancy may be due to a defect in the mechanism that converts granulosa and theca-lutein cells to luteal cells after the luteinizing hormone surge (or hCG administration). Data from the current study would suggest that the StAR protein may be involved.

Adult↗

PubMed1962

Observations on the fine structure of lutein cells.

Corpora lutea from the period of delayed implantation and from early postimplantation stages of the armadillo, mink, and rat were fixed in buffered osmium tetroxide-sucrose or potassium permanganate. After rapid dehydration, the portions of the corpora lutea were embedded in either methacrylate or epoxy resin. Examination of the lutein cells by electron microscopy revealed the presence, in the better preserved material, of an extensive development of tubular agranular endoplasmic reticulum. Although the membranes of the endoplasmic reticulum are the most striking feature of the lutein cells of both stages of the three animals examined, very numerous large mitochondria with cristae that exhibit a variety of forms tending toward villiform, and protrusions and foldings of the lutein cell margins on the pericapillary space are also characteristic of these cells. Certain minor differences in the lutein cells of the species examined are also noted. No indications of conversion of mitochondria into lipid, of accumulation of lipid in the Golgi area, or of the protrusion of lutein cells into spaces between the endothelial cells, as suggested by other authors, were noted in these preparations. Some of the difficulties inherent in the visualization of the secretory activity of cells producing steroid hormones are briefly discussed.

Animals↗

PubMed1966

Ovarian steroid cells. II. The lutein cell.

The lutein cells of the rabbit exhibit fine structural variations during their life-span of 28 to 30 days. A systematic examination of the corpus luteum reveals that cellular distinctions may be recognized during the first, second, and third stages of pregnancy. The agranular endoplasmic reticulum reveals vesicular, tubular, and cisternal profiles after fixation with each of the following fixatives: glutaraldehyde, osmium tetroxide, and permanganate. The osmolality of the fixing solutions was varied with sucrose and recorded with an osmometer in order to determine the effect of osmotic concentration on the intracellular membranous profiles. It was determined that vesicles and short, branched tubules of similar structure are present in the agranular reticulum when the osmolalities are 300 to 800 milliosmols (iso-osmotic considered 300 milliosmols). At 900 milliosmols, the vesicular or tubular lumen is obliterated. Intracellular membrane profiles do not exhibit interconversions due to hyperosmotic fixative solutions. The agranular endoplasmic reticulum is randomly distributed as short tubular profiles during the first third of pregnancy. A continuity between these membranes and irregular, electron-opaque lipid masses is evident. When physiological and histochemical data indicate that the lutein cell may be storing sterol precursors, cytological observations show that the agranular endoplasmic reticulum exists in a more organized pattern within the cytoplasmic matrix. Vesicular and short tubular, circular aggregations as well as whorled cisternal patterns surround the larger, less electron-opaque lipid droplets. Surface views of cisternal agranular endoplasmic reticulum exhibit tubular extensions, accentuating the continuity between these two profiles. During the progress of pregnancy, the lutein cell increases in diameter, and accumulates both lipid inclusions and aggregations of intracellular membranes. The agranular endoplasmic reticulum may be peripherally packed and arranged parallel to the cell surface during later stages. In the postpartum, degenerating lutein cell, large myelin figures are present which form from the agranular endoplasmic reticulum. These cellular events are discussed in relation to lutein cell activity, including both secretion of product and storage of precursors.

Animals↗

PubMed2006

Gonadotrophin stimulation of non-luteinized granulosa cells increases steroid production and the expression of enzymes involved in estrogen and progesterone synthesis.

BACKGROUND: In regular IVF treatment, mature oocytes are collected with their luteinized granulosa cells (GCs). When in vitro maturation (IVM) of the oocytes is performed, non-luteinized GCs can be collected. We have investigated how these cells respond to gonadotrophin stimulation in culture. METHODS: GCs were collected from patients undergoing IVM treatment and compared with GCs from IVF patients. The cells were stimulated with FSH and/or hCG. After 48 h, culture media were collected for hormone analysis, and RNA was isolated for gene expression analysis. RESULTS: In IVM GCs, hCG and FSH alone and in combination induced significantly increased progesterone production, and FSH alone and in combination with hCG increased estrogen production. We also studied the gene expression of P-450aromatase and P-450scc and the receptors for FSH and LH. In non-luteinized GCs, the expression levels of P-450aromatase increased with all treatments, and P-450scc expression increased with the combined FSH and hCG treatment. LHR expression increased with FSH treatment, but the FSH receptor expression did not change with different treatments. CONCLUSIONS: Non-luteinized GCs behaved differently from luteinized GCs in culture. The data help understand the final stages of maturation of human oocytes and follicles.

Aromatase↗

PubMed1999

Growth factor modulation of steroidogenic acute regulatory protein and luteinization in the pig ovary.

In vivo and in vitro luteinization were investigated in the porcine ovary, with emphasis on expression of steroidogenic acute regulatory protein (StAR). StAR mRNA and protein as well as cytochrome P450 side-chain cleavage mRNA (P450scc) increased during the luteal phase in the corpus luteum (CL) and were absent in regressed CL. Cytochrome P450 aromatase mRNA (P450arom) was not detectable at any time in CL. In vitro luteinization of granulosa cells occurred over 96 h in culture, during which P450arom mRNA was present at 1 h after cell isolation but not detectable at 6 h; and P450scc and StAR mRNAs were first detectable at 6 h and 48 h, respectively. Incubation of cultures with insulin-like growth factor I (IGF-I, 10 ng/ml), dibutyryl cAMP (cAMP, 300 microM), or their combination, induced measurable StAR mRNA at 24 h (p < 0.05), increased progesterone accumulation at 48 h, and elevated both StAR and P450scc expression through 96 h. Incubation of luteinized granulosa cells with epidermal growth factor (EGF, 10 nM) changed their phenotype from epithelioid to fibroblastic, eliminated steady-state StAR expression, and interfered with cAMP induction of StAR mRNA and progesterone accumulation. EGF had little apparent effect on P450scc mRNA abundance. It is concluded that StAR expression characterizes luteinization, and early luteinization is induced by cAMP and IGF-I in vitro. Further, EGF induces a morphological and functional phenotype that appears similar to an earlier stage of granulosa cell function.

Animals↗

PubMed1994

Sclerosing peritonitis associated with luteinized thecomas of the ovary. A clinicopathological analysis of six cases.

Six cases of a distinctive ovarian lesion associated with sclerosing peritonitis were found in patients 13 to 76 years of age. Five patients presented with abdominal swelling; on examination, three were found to have unilateral or bilateral pelvic masses, one had ascites and evidence of small bowel obstruction, and one had ascites alone. The sixth patient presented with small bowel obstruction. At operation, 1 to 9 L of ascitic fluid were found in five patients. Five patients with bilateral ovarian enlargement underwent bilateral oophorectomy or, in one case, bilateral ovarian wedge resection. The sixth patient had unilateral ovarian enlargement treated by unilateral oophorectomy. All had fibrotic thickening of the peritoneum, most prominently involving the omentum and small bowel, four at initial operation and two at a second operation performed shortly thereafter. One or more episodes of small bowel obstruction subsequently occurred in three of the five patients with follow-up. One woman died of pulmonary embolism 2 months after her initial operation; four were alive without clinical evidence of disease 8 months to 6 years postoperatively. Gross examination revealed unilateral (one case) or bilateral (two cases), predominantly solid ovarian tumors 12 to 31 cm in maximum dimension in three cases and slight enlargement and nodularity of both ovaries in the other three cases. Microscopic examination of the ovaries revealed a cellular proliferation of spindle cells with focal differentiation into nests of luteinized or partially luteinized cells; one case also had occasional foci of sex cord elements. The process was confined to the ovarian cortex in the three cases with slight ovarian enlargement. Residual ovarian follicles were entrapped by the proliferation in three cases, but were prominent in only one of them. Additional features included brisk mitotic activity, predominantly in the spindle cells, in three cases, and striking edema in the three cases with significant ovarian enlargement. The ovarian lesions were interpreted as luteinized thecomas, although a closely related hyperplasia with luteinization, instead of early neoplasia, cannot be excluded in the three cases with only slight ovarian enlargement (and in one, prominent entrapment of follicles). The peritoneal process consisted of a variably cellular proliferation of fibroblasts and myofibroblasts separated by collagen, fibrin, and occasional chronic inflammatory cells. These cases and two similar cases from the literature suggest a unique association between some luteinized thecomas (or a closely related proliferative lesion of the ovary) and sclerosing peritonitis, although the relation between the ovarian and peritoneal processes is presently enigmatic.

Adolescent↗

PubMed1993

Luteinizing hormone-releasing hormone and gamma-aminobutyric acid neurons in the medial preoptic area are synaptic targets of dopamine axons originating in anterior periventricular areas.

The aim of this study was to characterize further the transmitter content and the location of the parent cells of tyrosine hydroxylase-immunoreactive boutons terminating on luteinizing hormone-releasing hormone- and glutamic acid decarboxylase-immunoreactive neurons in the rat medial preoptic area. Electron microscopic immunostaining for luteinizing hormone-releasing hormone, tyrosine hydroxylase or glutamic acid decarboxylase was performed on desipramine-pretreated (to protect norepinephrine and epinephrine axons) rats which received a stereotaxic injection of 6-hydroxydopamine into the medial preoptic area anteroventral periventricular nucleus 48 h prior to sacrifice. This treatment induced acute degeneration of dopamine axon terminals characterized by the development of autophagous cytolysosomes, an early morphological sign of catecholamine axon degeneration. To further define the cells of origin of these dopamine boutons, the anterograde marker Phaseolus vulgaris leucoagglutinin was iontophoretically applied to the zona incerta. Six days later, rats received a 6-hydroxydopamine injection into the zona incerta or the lateral ventricle, and 48 h later, double immunostaining was performed for Phaseolus vulgaris leucoagglutinin and tyrosine hydroxylase, luteinizing hormone-releasing hormone, or glutamic acid decarboxylase on preoptic area vibratome sections. Following the 6-hydroxydopamine injection into the anteroventral periventricular nucleus, autophagous cytolysosome-containing degenerated axons were found in synaptic contact with both luteinizing hormone-releasing hormone and GABA neurons in the medial preoptic area, confirming that these are dopaminergic connections. Following the double injection treatment, 6-hydroxydopamine-induced degenerated, Phaseolus vulgaris leucoagglutinin-labeled dopamine axons originating in the zona incerta were not found to contact luteinizing hormone-releasing hormone-containing or GABA cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Ferredoxin reductase levels in the ovaries of pigs and superovulated rats during follicular cell growth and luteinization.

The concentration of ferredoxin reductase, a component of the mitochondrial steroidogenic electron transport chain, was measured in the ovaries of pigs and superovulated rats by a protein blotting procedure using polyclonal antibodies to the purified protein. The concentration of ferredoxin reductase in porcine granulosa cells doubled during growth of follicles from small (1-2 mm diameter) to large (6-12 mm diameter). The concentration doubled again during the period of luteinization. This is in contrast to the rate of cholesterol side-chain cleavage, which showed little change during follicular growth but increased by more than tenfold during luteinization. A similar large increase in cholesterol side-chain cleavage occurs during the period of luteinization in the ovaries of superovulated rats, but as for the pig, only a small increase in ferredoxin reductase was observed. A threefold increase in the yield of mitochondrial protein from tissue homogenates was found between the granulosa cells of small-medium follicles and the cells of the corpora luteum. The increase in ferredoxin reductase during follicular development and luteinization, therefore, correlates well with the increase in mitochondria in the cells, but does not correlate with the dramatic increase in cholesterol side-chain cleavage activity which occurs during luteinization. Based on these results, it is unlikely that the level of ferredoxin reductase limits the expression of the full steroidogenic activity of the granulosa cells of the ovary.

Animals↗

PubMed1998

In situ hybridization of high density lipoprotein (scavenger, type 1) receptor messenger ribonucleic acid (mRNA) during folliculogenesis and luteinization: evidence for mRNA expression and induction by human chorionic gonadotropin specifically in cell types that use cholesterol for steroidogenesis.

The present studies were undertaken to examine the expression of the high density lipoprotein (HDL) receptor, SR-B1 messenger RNA (mRNA) in ovarian cell types during folliculogenesis and luteinization using in situ hybridization histochemistry and to examine its hormonal regulation using Northern blots. For the in situ study for HDL receptor mRNA localization, 21-day-old rats were treated with 50 IU PMSG, and ovaries were collected 0, 24, and 56 h postinjection. At 56 h, animals were treated with a single dose of hCG, and ovaries were subsequently collected at 6-, 12-, 24-, and 72-h and 5-day intervals. In addition, on day 4 of pseudopregnancy, a second dose of 50 IU hCG or saline was administered, and ovaries were collected at 12, 24, and 48 h to determine the induction of the expression of HDL receptor mRNA. The results of in situ hybridization histochemistry showed that in the immature ovary, HDL receptor mRNA is associated with theca interna and interstitial cells (stroma). The mRNA expression in these cell types increased with PMSG treatment, but no signal was detected in the granulosa cells. Northern blot analysis also showed a marked increase in mRNA content in thecal and interstitial cells during follicular development. During luteinization, the intensity of the signal began to appear in the luteinized granulosa cells. With the completion of luteinization, the signal in the corpus luteum tissue became more intense. Further treatment with hCG increased the HDL receptor mRNA content compared with that in the saline-treated control. These results demonstrate that the cholesterol-using cell types of the ovary, namely the interstitial cells, thecal cells, and fully luteinized granulosa cells are endowed with the HDL receptor mRNA, which provides credence to the functional significance of the role of HDL receptor SR-B1 in cholesterol transport and ovarian steroidogenesis.

Animals↗

PubMed1979

Luteinization of bovine granulosa cells and corpus luteum formation associated with loss of androgen-aromatizing ability.

The relative aromatizing ability of bovine luteinizing granulosa cells and dispersed luteal cells in tissue culture was studied. Luteinization of granulosa cells, as indicated by steadily increasing progesterone production (from 50 to 300 ng/10(5) cells/day over 4--5 days), was accompanied by a dramatic reduction in their capacity to aromatize exogenous androgen; oestradiol-17 beta production falling from 200 to less than 10 ng/10(5) cells/day over 4--5 days. Luteal cells also had only a very limited capacity to aromatize exogenous androgen, maximum oestradiol-17 beta production being less than 600 pg/10(5) cells/day. The loss in aromatizing capacity of granulosa cells during luteinization was also reflected in the relative endogenous steroid content of non-luteinized granulosa cells and luteal tissue, the former containing high levels of oestradiol-17 beta, less than or equal to 28 ng/mg protein, while the latter, although containing substantial amounts of testosterone, less than or equal to 5.7 ng/g tissue, contained very little oestradiol-17 beta, less than or equal to 0.35 ngG TISSUE. These findings suggest that luteinization of bovine granulosa cells and subsequent corpus luteum formation is associated with a loss in androgen aromatase activity.

Animals↗

PubMed1996

Follicular variation in ovarian 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) activities: evidence for the paracrine inhibition of 11 beta HSD in human granulosa-lutein cells.

We have previously shown that detectable metabolism of cortisol to cortisone by 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) in human granulosa-lutein cells, pooled for each patient from all aspirated ovarian follicles, is associated with failure to conceive by in vitro fertilization and embryo transfer. The aims of the present study were to assess: (1) the variation in the 11 beta HSD activities of granulosa-lutein cells obtained from individual follicles in relation to oocyte maturity and (2) whether the 11 beta HSD activity of pooled granulosa-lutein cells reflects the 11 beta HSD activities of the individual follicles for a given patient. 11 beta HSD activities were measured in intact cells in serum-free medium by a radiometric conversion assay (100 nmol/l [3H]cortisol to [3H]cortisone). Follicular 11 beta HSD activities ranged from < 10 (undetectable) to 514 pmol/mg protein per 4 h (n = 105 follicles from 12 patients) and did not correlate with oocyte maturity. In three separate patients, the follicular 11 beta HSD activities ranged from < 10 to 117 pmol/mg protein per 4 h (n = 8 follicles), 19 to 514 pmol/mg per 4 h (n = 9) and 60 to 390 pmol/mg per 4 h (n = 8). The 11 beta HSD activities of the corresponding multi-follicular pools of cells were < 10, < 10 and 44 pmol/mg per 4 h respectively, all of which were significantly lower (P < 0.05) than the arithmetic means for the activities in the individual follicles (52, 132 and 215 pmol/mg per 4 h respectively). Likewise, the 11 beta HSD activities of two independent multi-patient pools of cells were significantly lower than the mean values of the 11 beta HSD activities of the appropriate individual patients. We conclude that ovarian 11 beta HSD activity varies between follicles and that co-culture of granulosa-lutein cells with low enzyme activity can suppress the ovarian 11 beta HSD activity in cells from different follicles (or patients) with high rates of cortisol metabolism. Hence, these data indicate the potential for paracrine inhibition of ovarian 11 beta HSD activity in human granulosa-lutein cells.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2001

[Effects of leptin on estradiol and progesterone production by human luteinized granulosa cells in vitro].

OBJECTIVE: To investigate the effects of leptin on steroidogenesis of human luteinized granulosa cell in vitro. METHODS: Human luteinized granulosa cells were isolated from follicular fluid obtained during oocyte retrieval of in vitro fertilization-embryo transfer program and were cultured with M199 medium plus various concentration of leptin (0, 10, 30, 100, 300 ng/ml), human menopausal gonadotropin (hMG, 0, 0.1, 0.2, 0.5, 1, 2, 5, 10 IU/ml) and testosterone 100 micrograms/ml. For 2 days the media were collected for estradiol and progesterone measurements. RESULTS: Addition of leptin alone did not alter estradiol and progesterone production (P > 0.05) by human luteinized granulosa cells. Leptin of 10-30 ng/ml concentrations caused a dose-dependent inhibition of estradiol production (P < 0.05) while greater than 0.5 IU/ml of hMG were added. There was no effect of leptin on hMG-stimulated progesterone production (P > 0.05). CONCLUSION: Leptin can directly inhibit hMG-stimulated estradiol production by human luteinized granulosa cells in vitro, but has no effect on progesterone production. Leptin may play an important role in follicle development and luteinization.

Cells, Cultured↗