[Characteristic and evolution of pacemaker complications in a Subsaharan Africa Heart Centre]. / Caractéristiques et évolution des complications de la stimulation cardiaque dans un centre de cardiologie de l'Afrique de Subsaharienne.

AIM OF THE STUDY: The working environment and the low rate of pacemaker insertions increase the risk of complications in sub-Saharan Africa. The objective of our work was to assess the impact of specific preventive measures on these complications over the long term. PATIENT AND METHODS: We conducted a retrospective study of all pacemaker implantations from June 2006 to June 2016 at the Abidjan Heart Institute. We evaluated the incidence of pacemaker complications, their risks factors and their impact on the overall prognosis of patients. RESULTS: Three hundred and two procedures were performed in 286 patients (49% male, mean age: 67±12 years), with a predominance of primary implantation (82.8%) of single-chamber ventricular pacemakers (66.6%). Twenty-five major complications (8.27%) and 14 minor (4.6%) occurred with a predominance of lead displacements (3.64%). The major complications were favored by the subclavian approach (P=0.018; OR=2.34; 95% CI [1.16-4.75]) and intraoperative incidents (P=0.02; OR=2.17; 95% CI [1.16-4.75]. The preventive measures taken made it possible to achieve a significant (P=0.017) and linear (P=0.009) reduction of these complications, with no effect the patients prognosis (Log-Rank=0.217; P=0.64). CONCLUSION: Quality cardiac stimulation is possible in Sub-Saharan Africa with preventive measures adapted to the environment.

Above 25†nm emission wavelength shift in blue-violet InGaN quantum wells induced by GaN substrate misorientation profiling: towards broad-band superluminescent diodes.

We report a thorough study of InGaN quantum wells spatially modified by varying the local misorientation of the GaN substrate prior to the epitaxial growth of the structure. More than 25 nm shift of emission wavelength was obtained, which is attributed to indium content changes in the quantum wells. Such an active region is promising for broadening of the emission spectrum of (In,Al,Ga)N superluminescent diodes. We observed that the light intensity changes with misorientation, being stable around 0.5° to 2° and decreasing above 2°. This relation can be used as a base for future device designing.

[Prevalence and characteristics of acute coronary syndromes in a sub-Saharan Africa population]. / Prévalence et caractéristiques des syndromes coronariens aigus dans une population d'Afrique subsaharienne.

AIM: To assess prevalence, characteristics and management of acute coronary syndromes in sub-Saharan Africa population. PATIENTS AND METHODS: Prospective survey from January, 2010 to December, 2013, carried out among patients aged 18 years old, admitted to intensive care unit of Abidjan Heart Institute for acute coronary syndrome (ACS). RESULTS: Four hundred and twenty-five (425) patients were enrolled in this study. Prevalence of ACS was 13.5%. Mean age was 55.4±11 years. Clinical presentation was predominantly ST-segment elevation myocardial infarction (STEMI) in 71.5% of subjects, non-ST-segment elevation acute coronary syndrome (NSTE-ACS) accounted for 28.5%. Two hundred and eighty patients (65.9%) were transferred by unsafe transportation. Among the 89 patients admitted within 12hours of the onset of symptoms, primary percutaneous coronary intervention was performed in 20 patients (22.5%), or 6.6% of STEMI as a whole. Twenty-five patients (8.2%) received fibrinolytic therapy with alteplase. In-hospital death rate was 10%. CONCLUSION: The prevalence of acute coronary syndromes is increasing in sub-Saharan Africa. Excessive delays of admission and limited technical facilities are the major difficulties of their management in our regions.

An optofluidic constriction chip for monitoring metastatic potential and drug response of cancer cells.

Cellular mechanical properties constitute good markers to characterize tumor cells, to study cell population heterogeneity and to highlight the effect of drug treatments. In this work, we describe the fabrication and validation of an integrated optofluidic chip capable of analyzing cellular deformability on the basis of the pressure gradient needed to push a cell through a narrow constriction. We demonstrate the ability of the chip to discriminate between tumorigenic and metastatic breast cancer cells (MCF7 and MDA-MB231) and between human melanoma cells with different metastatic potential (A375P and A375MC2). Moreover, we show that this chip allows highlighting the effect of drugs interfering with microtubule organization (paclitaxel, combretastatin A-4 and nocodazole) on cancer cells, which leads to changes in the pressure-gradient required to push cells through the constriction. Our single-cell microfluidic device for mechanical evaluation is compact and easy to use, allowing for an extensive use in different laboratory environments.

An integrated optofluidic device for single-cell sorting driven by mechanical properties.

We present a novel optofluidic device for real-time sorting on the basis of cell mechanical properties, measured by optical stretching. The whole mechanism, based on optical forces, does not hamper the viability of the tested cells, which can be used for further analysis. The device effectiveness is demonstrated by extracting a sample population enriched with highly metastatic cells from a heterogeneous cell mixture.

Anevrisme du ventricule gauche associe a une infection par le VIH chez un enfant de 13 ans

Contexte. Les anevrismes ventriculaires sont rares chez les enfants; et les theories concernant les facteurs etiologiques varient. Les objectifs. etaient de decrire l'experience d'un cas clinique et discuter les particularites de cette pathologie diagnostiquee chez un enfant infecte par le VIh. Patient et Methode. Il s'agit d'une etude prospective d'un anevrisme du ventricule gauche associe a une infection par le VIh1 chez un enfant de 13 ans a l'institut de cardiologie d'Abidjan. Resultats. Il s'agissait d'un enfant de 13 ans; de sexe masculin qui consultait pour une douleur thoracique associee a des palpitations puis une dyspnee d'effort. Le tableau clinique etait celui d'une douleur precordiale. L'electrocardiogramme a objective une hypertrophie ventriculaire gauche. L'echocardiographie Doppler objectivait un large anevrisme du ventricule gauche. L'indication d'une cure chirurgicale a ete retenue. Le bilan biologique preoperatoire a objective une serologie retrovirale positive pour le VIh 1. Ce patient n'a pas encore ete opere du fait de l'absence de couverture sociale. Il a ete traite avec de l'aspirine. Conclusion. Cette association; anevrisme du ventricule gauche et infection a VIh; est certes rare chez l'enfant mais avec la persistance de l'endemie VIh/SIDA dans notre milieu ; on pourrait en decouvrir d'avantage si les explorations en cardiologie sont vulgarisees

Picrotoxin but not bicuculline partially abolishes the cardio-inhibitory responses induced by visual stimulation in the crab Neohelice granulata.

Conspicuous and sustained heart arrests, revealed as an increase in the magnitude of cardiac interbeat intervals, are elicited in the crab Neohelice granulata upon the presentation of a visual danger stimulus (VDS). Aiming to study the regulation of cardio-inhibitory responses (CIR) in vivo, we investigated whether GABA mediates the extrinsic regulation of the cardiac activity. We examined the possibility of abolishing CIR by injecting the GABAergic antagonists picrotoxin and bicuculline, right before sensory stimulation. Picrotoxin partially abolished the reversible cardiac arrests induced by VDS, whereas bicuculline showed no effects. These results suggest that the rapid responses of the cardiac system of the crab Neohelice to environmental disturbances, reminiscent of an autonomic-like regulation associated with fear, flight or fight, may be extrinsically regulated by the GABAergic system.

Memory consolidation and reconsolidation in an invertebrate model: the role of the GABAergic system.

Consolidation theory assumes that memories are labile during a limited time window after acquisition, but as time passes, memories become stable and resistant to amnesic agents. However, the vision of immutable memories after consolidation has been challenged. Thus, after the presentation of a reminder, the reactivated old memories become labile and again susceptible to amnesic treatments. This process implies a re-stabilization phase, usually referred to as reconsolidation. Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter both in the Central nervous system (CNS) and in the periphery. A considerable amount of evidence has arisen from different studies regarding the role of the GABA(A) receptor in diverse behavioral paradigms and tasks. Here, we investigate the role of the GABAergic system on both memory consolidation and reconsolidation phases by using the memory paradigm of the crab Chasmagnathus. In order to achieve such a goal, we design pharmacological-behavioral experiments, which include the administration of classic agonist (muscimol) and antagonist (bicuculline) of the mammals GABA(A) receptors. The current results show that the systemic administration of muscimol impairs the consolidation and reconsolidation processes. In contrast, the administration of bicuculline improves the consolidation and reconsolidation processes. Furthermore, the co-administration of both drugs blocks the agonist amnesic effect on the consolidation phase. The ubiquity of the neurotransmitter and its receptors in the animal taxa allows us to use the classic agonist-and-antagonist administration procedure in this invertebrate. Thus, all the results reported in this paper can be judged as a result of the modulation exerted by the functional state of the GABAergic system in the CNS. To conclude, the results obtained in this report with an invertebrate model represent additional evidences supporting the view that some molecular mechanisms subserving different memory phases could be the basic tools employed by phylogenetically disparate animals.

[Clinical study on the cases in which INH or RFP was discontinued during treatment for pulmonary tuberculosis].

Short course regimens; 2HRZ (E)(S)/4HR (E), 6HRS (E)/3-6HR and 6-9HR have been accepted as a standard chemotherapy (SC) for initial treatment of pulmonary tuberculosis in Japan. We studied the frequency of the treatment completion, the causes of the treatment failure and the outcome of the patients in whom INH or RFP was discontinued within 6 months after starting SC. The subjects included 597 newly diagnosed culture positive pulmonary tuberculosis patients admitted to 16 national hospital in 1996. Results were as follows. 1. In 47 (7.9%) of the 597 patients, either INH (19; 3.2%) or RFP (33; 5.5%) was discontinued. These 47 cases were defined as a SC incompleted group and the other 550 as a SC completed group. 2. The patients in the SC incompleted group were seen more frequently in the ages of 20s (11.9%), 50s (10.9%), 60s (11.7%) or 70s (11.4%). 21 (13.6%) of 154 female patients and 26 (5.9%) of 443 male patients were in the SC incompleted group. 3. The causes of cessation of INH or RFP were drug side effects (33; 5.5%), drug resistance (10; 1.7%) and complications or underlying diseases (8; 1.3%). 4. Fever or eruption (19; 3.2%) and drug induced hepatitis (12; 2.0%) were frequently seen as drug related side effects causing the cessation of INH or RFP. 5. The rate of culture negative conversion of TB bacilli at 6 months after the start of the treatment was 98.9% in the SC completed and 88.9% in the SC incompleted group respectively. In the SC incompleted group, there were three cases continuously positive and two other patients who relapsed and became culture positive again. In these five patients, INH or RFP was discontinued because of drug resistance.

Expression of gonadotropin and activin receptor messenger ribonucleic acid in human ovarian epithelial neoplasms.

Activin receptors (ActRs) and gonadotropin receptor mRNA expression were investigated in 18 human ovarian epithelial neoplasms. Northern blot analysis showed the presence of 3.0-kb type Ia ActR, 6.0- and 3.0-kb type IIa ActR, and 5.0-kb type IIb ActR mRNA transcripts in total RNA prepared from the cancer tissues. One carcinoma showed two major transcripts of a follicle-stimulating hormone receptor (FSH-R) gene, 4.1 and 2.4 kb, whereas the other two carcinomas showed two major transcripts of the luteinizing hormone/human chorionic gonadotropin receptor (LH-R) gene, 5.4 and 2.4 kb. These results were further analyzed by studying the corresponding PCR-amplified FSH and LH-R cDNA obtained by reverse transcription of total RNA. Expression of FSH-R mRNA was confirmed in about half of the cancer tissues. The size of the FSH-R reverse transcription-PCR product was the same as in normal ovarian follicles. Similarly, expression of LH-R mRNA was also detected in about half of the cancers. Normal ovaries and cancer tissues were homogenized, and activin concentrations were measured in extracts. Activin levels in normal ovarian tissue were around 0.59 +/- 0.01 ng/mg protein (mean +/- SE; n = 5), and activin production was detected in every cancer tissue, except one--serous adenocarcinoma. The findings in this study demonstrated that activin and ActRs are present in and synthesized by human ovarian epithelial neoplasms. Thus, activin seems to be available as an autocrine/paracrine factor in epithelial neoplasms and may contribute to the expression of FSH-R, although the roles of activin and gonadotropin in tumorigenesis has yet to be defined.

The mechanisms of retinoic acid-induced regulation on the follicle-stimulating hormone receptor in rat granulosa cells.

The present study was undertaken to identify the mechanisms underlying the effect of retinoic acid (RA) on follicle-stimulating hormone receptor (FSH-R) in rat granulosa cells. Treatment with FSH produced a substantial increase in FSH-R mRNA level, as was expected, while concurrent treatment with increasing concentrations of RA brought about dose-dependent decreases in FSH-induced FSH-R mRNA, with a maximal inhibition one-third lower than that induced by FSH alone. RA, either alone or in combination with FSH, did not affect intracellular cAMP levels, while it inhibited the effect of 8-Br-cAMP on FSH-R mRNA production. These results suggested that RA diminished the action of FSH on FSH-R expression at sites distal to cAMP generation in the granulosa cells. Whether the effect of RA and FSH on FSH-R mRNA levels was the result of decreased transcription and/or altered mRNA stability was also investigated. The rate of FSH receptor mRNA gene transcription, assessed by nuclear run-on transcription assay, was found to decrease by the addition of RA. On the other hand, the decay curves for the 2.4 kb FSH-R mRNA transcript in primary granulosa cells did not alter the slope of the FSH-R mRNA decay curve in the presence of RA. Our data suggests for the first time that the effect of RA on FSH-R expression is possibly mediated by the reduction of the FSH-R mRNA level due to a negative regulation of the FSH-R gene in the presence of FSH. These findings assist in understanding the molecular mechanism underlying the effect of RA on reproductive function in rat granulosa cells.

Lack of interaction in recombinant human FSH receptor and both TSAb and TSBAb.

Since cross-reactivity of TSH with the human FSH receptor has been reported, in this study we tested the effect of thyroid-stimulating antibody (TSAb) and thyroid stimulation-blocking antibody (TSBAb) on Chinese hamster ovary cells expressing human FSH receptor (CHO-hFSH-R cells). We examined the TSBAb activity of sera from hypothyroid patients who had a positive TBII to determine whether these sera also block the effect of FSH on CHO-hFSH-R cells. Although human FSH I-3 (0.25-16 ng/ml) stimulated the production of intracellular cAMP in CHO-hFSH-R cells with dose-responsive manner, neither TSAb nor TSBAb had such an effect on the cells.

Effect of prolactin on the expression of luteinizing hormone receptors during cell differentiation in cultured rat granulosa cells.

Chronic and transient hyperprolactinemia has been associated with luteal phase dysfunction. Recently, evidence has emerged to suggest that elevated PRL may exert its antigonadal effects through reducing available ovarian LH receptors. We have now examined the influences of PRL on LH receptor induction in cultured granulosa cells. Basal specific LH binding was negligible and remained unchanged in response to treatment with PRL by itself. Whereas treatment with FSH produced, as expected, a substantial increase in specific LH binding, concurrent treatment with PRL resulted in no significant change during the first 4 days of culture, followed by a significant decrease in LH binding on days 5 and 6 as well as an approximately 50% inhibition of FSH effect on day 6. Scatchard plot analysis showed that concurrent treatment with PRL resulted in inhibition of the granulosa cell LH binding capacity, whereas no difference could be detected in the binding affinity of LH to its receptor. Treatment with 8-bromo-cAMP produced a significant increase in specific LH binding; concurrent treatment with PRL (30 ng/ml) produced a significant attenuation of 8-bromo-cAMP action. In addition, treatment with FSH increased the intracellular accumulation of cAMP, and concurrent treatment with PRL did not result in inhibition of the FSH action, as assessed by the generation of intracellular cAMP. Taken together, these findings suggest that the ability of PRL to interfere with FSH action with regard to the induction of LH receptors is exerted at sites distal to those involved in cAMP generation. The effect of PRL on LH receptor messenger RNA (mRNA) levels was not significant during the increase in receptors, whereas after the maximal level of receptor expression was reached, the effect of PRL was apparent. Cotreatment with FSH (30 ng/ml) and increasing doses of PRL inhibited the levels of FSH-induced LH receptor mRNA in a dose-dependent manner, whereas PRL did not inhibit the effect of FSH on the FSH receptor mRNA. To investigate the hormonal regulation of the 5'-flanking region, we analyzed the effect of FSH on 1379 bp of LH receptor promoter in rat granulosa cells. Treatment with FSH (1-100 ng/ml) significantly enhanced the activity of 1379 bp of the LH receptor 5'-flanking region in dose-dependent manner. Treatment with 30 ng/ml PRL alone did not significantly influence the activity of the LH receptor promoter and did not affect the increased promoter activity induced by FSH. In addition, the rates of LH receptor mRNA gene transcription assessed by nuclear run-on transcription assay increased by the addition of FSH and were not affected by the addition of PRL in the presence of FSH. These data showed that PRL might not effect LH receptor gene transcription in the regulation of LH receptor mRNA. Next, an attempt was made to determine the effect of PRL on LH receptor mRNA stability by measuring the decay of LH receptor mRNA under conditions known to inhibit transcription. However, inhibitors of transcription were found to have a stabilizing effect on the LH receptor mRNA, thus potentially masking the effect of PRL. According to the expression of LH receptor mRNA, PRL might not affect the maximum level induced by FSH, but thereafter the maximum levels of LH receptor mRNA decreased faster than those of the control. Therefore, it may be possible that PRL acts to stimulate labile LH receptor mRNA-destabilizing factors.

Adrenomedullin and atrial natriuretic peptide concentrations in normal pregnancy and pre-eclampsia.

Adrenomedullin (AM) is a peptide that elicits a long-lasting vasorelaxant activity, while atrial natriuretic peptide (ANP) has also been shown to be a potent vasodilatory agent. To clarify the possible role of AM and ANP in the physiology of pregnancy and pathophysiology of pre-eclampsia, we measured plasma concentrations of these peptides in non-pregnant women, normal pregnant women and women with pre-eclampsia. A gradual increase in plasma AM was observed as pregnancy progressed. The plasma AM concentrations during the second trimester (12.7 +/- 1.4 fmol/ml) were significantly elevated, in comparison with the non-pregnant follicular phase (6.4 +/- 0.61 fmol/ml), luteal phase (6.0 +/- 0.49 fmol/ml), and the first trimester (6.5 +/- 0.8 fmol/ml). The plasma AM concentrations of the third trimester (21.5 +/- 1.4 fmol/ml) were significantly elevated when compared with those of the second trimester (P < 0.05). Northern blot analysis confirmed the expression of the AM mRNA transcript (1.6 kb) in third trimester placentas. In comparison with those observed at term (25.3 +/- 4.5 fmol/ml), the plasma concentrations were significantly reduced post-partum (6.4 +/- 0.6 fmol/ml). In the third trimester, plasma AM concentrations did not differ significantly between women with pre-eclampsia (17.2 +/- 2.3 fmol/ml) and normal pregnant women. In contrast, the plasma ANP concentrations in pre-eclampsia (39.5 +/- 7. 1 pg/ml) were significantly elevated when compared with those of the normal third trimester (14.4 +/- 1.4 pg/ml) (P < 0.05). ANP concentrations were reasonably constant throughout the pregnancy.

Control of the expression of luteinizing hormone receptor by local factors in rat granulosa cells.

To identify the mechanisms underlying the hormone-dependent induction and maintenance of luteinizing hormone receptor (LH-R) in rat granulosa cells, the effect of follicle-stimulating hormone (FSH) and local factors on the LH-R mRNA levels were studied. LH-R mRNA levels of the cells incubated with FSH decreased rapidly after medium removal, and readdition of FSH with the fresh medium did not restore these levels. On the other hand, 8-bromoadenosine 3,5-cyclic monophosphate significantly enhanced the expression of LH-R mRNA after medium removal, while the level of LH-R mRNA was lower than that of the cells replaced by original medium including FSH. In addition, the incubation with 8-Br-cAMP produced dose-dependent responses for LH-R mRNAs and enhanced the activity of 1379 bp of the LH-R 5'-flanking region, while the level of LH-R mRNA decreased 3 days after medium removal. Further studies were undertaken to assess the role of factors in maintaining the LH receptor once induced by FSH. Since FSH and cAMP increase follistatin production in granulosa cells, we examined the effect of follistatin on LH-R induction in the presence of activin and FSH. Activin induced LH-R in the presence of FSH significantly, and follistatin antagonized this effect in a dose-dependent manner. However, insulinlike growth factor-I (IGF-I) induced LH-R mRNA in the presence of FSH even after medium change. IGF-I might be one of the important factors that act in the medium to maintain LH-R levels in granulosa cells.

Control of FSH receptor mRNA expression in rat granulosa cells by 3',5'-cyclic adenosine monophosphate, activin, and follistatin.

FSH is required to maintain FSH and LH/hCG receptors at elevated steady-state levels after receptor induction. Although this function of FSH is mediated by cAMP, how cAMP level is related to the maintenance of gonadotropin receptors is unknown. To investigate cAMP's effect on changes in the levels of FSH receptor mRNAs in rat granulosa cells, total RNA from cells was prepared and analyzed by Northern blots. Incubation with 8-Br-cAMP for 24 h produced a dose-related increase in FSH receptor mRNA in granulosa cells of DES-primed immature rats. On the other hand, 8-Br-cAMP, washed at 24 h, exerted inverse dose-related effects on FSH receptor mRNA levels at 96 h. The addition of 1 mM cAMP resulted in higher levels of FSH receptor mRNA than that induced by 0.2 mM cAMP at 24 h, while 0.2 mM cAMP is as effective as 1-2 mM cAMP for the induction of FSH receptor mRNA at 96 h. To further analyze cAMP's role in the production of activin in granulosa cells, we measured activin levels in the culture medium after the addition of 8-Br-cAMP. The levels of activin A were suppressed by the addition of 8-Br-cAMP in a dose-dependent manner. In addition, the procedure by which 8-Br-cAMP was removed after 24 h incubation showed that the level of activin in the medium increased after medium change. With regard to the actions of activin A on gonadotropin receptors, our laboratory has demonstrated that activin A increases the levels of FSH receptor mRNAs. Therefore, cAMP has a negative effect on FSH receptor expression by suppressing the activin level. Since follistatin production is up-regulated by cAMP in this system, we examined the effect of follistatin on FSH receptor mRNA level, which is induced by activin and FSH. Cotreatment with follistatin (0-100 ng/ml) and activin (50 ng/ml) in the presence of FSH (30 ng/ml) caused a significant reduction in FSH receptor mRNA levels induced by activin. Based on these observations, it is possible that cAMP has both stimulatory and inhibitory effects on the expression of gonadotropin receptors, and the overall influence of cAMP on their expression might be determined by the integration of such opposing effects.

The effect of follicle-stimulating hormone (FSH) on the expression of FSH receptor in cultured rat granulosa cells.

The acquisition of FSH receptors during folliculogenesis is believed to be a key event in the subsequent development of the follicle. The regulation by FSH of FSH receptor expression and function were further studied using cultured granulosa cells of diethylstilbestrol (DES)-primed immature rats. Incubation of rat granulosa cells with FSH led to a reduction in FSH receptor levels for a short time (6 h), followed by an increase in FSH receptor levels that reached maximum of around 150% of the initial level within 3 days after the addition of FSH. FSH stimulation caused a reduced cAMP response to subsequent FSH treatment and a time course experiment demonstrated that this response was detectable within 30 min of exposure to FSH and reached a plateau after 4 h to 24 h. The recovery of FSH responsiveness in cAMP production of granulosa cells was seen after 48 h of FSH-free interval. Treatment with forskolin (FSK) enhanced the effect of subsequent FSH on the production of intracellular cAMP. Treatment with PMA did not affect the response to subsequent FSH treatment. These data showed that the FSH is essential for the suppression of the FSH receptor function in the adenylyl cyclase pathway. Desensitization of cellular response to continuous agonist stimulation may occur because of changes in the numbers of FSH receptor, as well as changes in the functional properties of the effector system.

Expression and effect of adrenomedullin on rat granulosa cell.

Adrenomedullin (AM) is a potent hypotensive peptide recently discovered in extracts of human pheochromocytoma. To elucidate the regulation of AM production in the ovary, the effect of gonadotropin on the production of AM was studied in the cultured rat granulosa cells. A Northern blot analysis of the LH receptor and adrenomedullin yielded a major hybridizing band at 5.4 kb and 1.6 kb, respectively. In our culture system of rat granulosa cells, without any stimulus, the LH receptor mRNA was undetectable and the AM mRNA level was stably expressed for 6 days. FSH significantly induced LH receptor mRNA and suppressed AM mRNA for 4 days of culture and with the addition of hCG after 2 days of pretreatment with FSH, AM mRNA levels were markedly suppressed. FSH and 8-Br-cAMP significantly increase LH receptor mRNA and suppress AM mRNA in a dose-dependent manner. These data indicated that the differentiation of granulosa cells mediated by gonadotropins were associated by suppression in AM expression through a cAMP-dependent mechanism. On the other hand, AM stimulated a rapid rise in intracellular cAMP levels, which peaked within 15 min of addition, in a dose-dependent manner with a maximal response seen at 100 nM. Additionally, AM enhanced the effects of FSH, acting additionally to produce cAMP in the cells. AM may play a role in the process of granulosa cell differentiation as a local regulator through an autocrine/paracrine mechanism.

The effect of activin and FSH on the differentiation of rat granulosa cells.

The differentiation of granulosa cells is regulated by follicle-stimulating hormone (FSH) and local ovarian factors. To further analyze the role of FSH and activin in this process, we have examined the effect of FSH and activin on FSH and luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor induction in granulosa cells. Granulosa cells from diethylstilbestrol (DES)-primed immature rats produce activin and maintain FSH receptor without LH/hCG receptor expression in the absence of FSH. On the other hand, FSH induced granulosa cells to differentiate into more mature granulosa cells in which higher LH/hCG receptor expression and diminished activin production were observed.

Follicle-stimulating hormone regulation on its receptor messenger ribonucleic acid levels in cultured rat granulosa cells.

Our studies using immature rat granulosa cells cultured in serum-free medium on collagen-coated dishes indicated that FSH receptor mRNA levels do not change for at least 4 days of culture in the absence of hormone treatment. Addition of FSH (30 ng ml[-1]) led to a reduction of FSH receptor mRNA for a short time (6 h), followed by an increase in FSH receptor mRNA levels that reached maximum of around 200% of the initial level within 2-3 days after the addition of FSH. Following the addition of 10 nM PMA, FSH receptor mRNA levels were decreased to 50% of the pretreatment levels. During prolonged exposure to PMA, gradual recovery of the FSH receptor mRNA level was observed, and it was significantly higher than the control level at 48 h. The inactive phorbol ester 4 alpha-phorbol-12,13-didecanoate did not depress FSH receptor mRNA levels. Downregulation of the FSH receptor mRNA was detectable at a PMA concentration of 1 nM. The two predominant FSH receptor mRNA transcripts, ca. 5.5 and 2.4 kb, respectively, appeared to be equally affected by SH and PMA treatments. To examine the role of PKC mediation of the effect of FSH on FSH receptor mRNA levels, granulosa cells were treated with the PKC inhibitor, H-7, and FSH. Although, FSH receptor mRNA levels decreased to 50% of control in the cells treated with FSH alone, the addition of H-7 (0.1 nM) caused no decline in FSH receptor mRNA levels relative to the control in the cells treated with FSH. On the other hand, inhibition of FSH receptor mRNA by FSH was partially suppressed by the PKC-selective inhibitor bisindolylmaleimide. The mRNA turnover experiments showed that the half-life of FSH receptor transcripts was unaffected by PMA exposure.