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N Cherradi

Publications and source records attributed to N Cherradi.

At least 19 recordsLinked to original sources
PubMed2004

[Clear cell sarcoma of the kidney. A study of 13 cases].

UNLABELLED: Clear cell sarcoma of the kidney (CCSK) also called a "bone-metastasizing renal tumor of childhood" is the second common pediatric renal neoplasm. This tumor is associated with a higher rate of relapse and a wider distribution of metastases than Wilms' tumor. PATIENTS AND METHODS: We have reviewed records of 13 cases of CCSK among 277 renal tumors (5%) diagnosed at the children's hospital of Rabat between 1990 and 2002. RESULTS: The median age at diagnosis was 14 months (5 months-9 years). The male to female ratio was 5.5:1.00. Abdominal mass, usually the first physical finding, was associated with hematuria in four cases. No congenital malformation syndrome or familial Wilms' tumor were observed. Imaging studies found out seven right and six left intrarenal processes. Preoperative chemotherapy was given according to the SIOP9, SIOP93-01 and GFAOP 98 protocols. Twelve of 13 children underwent nephrectomy. Tumor measurements varied through 450-3450 g and 7-26 cm. The classic morphologic pattern was seen in nine cases (69%). The distribution local stage was I: three cases; II: three cases; III: six cases; IV: one case. Postoperative chemotherapy and radiotherapy (21 600-30 600 cGy) was done in 10 cases. With a median follow up of 44 months, four patients showed bone metastases (31%), four are alive in CR, four are lost for follow up and five died. CONCLUSION: CCSK remains the pediatric renal tumor most frequently misdiagnosed. Its aggressiveness and its ability to give bone metastases need to recognize early this diagnosis for an adapted treatment.

Age of Onset↗
PubMed2004

[Chondromyxoid fibroma of bone: a rare benign bone tumor in children].

Chondromyxoid fibroma is a rare benign tumor that is typically found in the metaphyseal ends of long tubular bones, such as the tibia. The radiographic appearances are those of a single, lytic lesion with lobulated margins, septations, cortical expansion and a sclerotic rim. The classic histological feature of a chondromyxoid fibroma is stellate or spindle-shaped cells arranged in lobules in a myxoid or chondroid background. Two cases are presented here: 8, and 12-year-old patients, both with lesions in the proximal tibia. The first case showed an unusual feature: it was diaphyseal chondromyxoid fibroma. In the second case, the lesion was metaphyso-diaphyseal. The differential diagnosis includes chondroblastoma, myxoma, aneurysmal cyst as well as chondrosarcoma. A surgical conservative treatment with complete excision is recommended even in case of recurrence.

Bone Neoplasms↗
PubMed2003

[Benign granular cell anal tumor].

INTRODUCTION: Granular cell tumors (GCT) are rarely located in the perianal area. OBSERVATION: Over the past 3 years, a 56 year-old man presented a papule of the right margin of the anus that had progressively increased in size (1.5 cm). Cell proliferation was located in the dermis and strongly expressed the S100 protein. It was covered by a pseudo-epitheliomatous hyperplasia of the overlying epidermis. Forty months after local surgical excision, there was no sign of recurrence. COMMENTS: Granular cell tumors are rare and usually benign. When cutaneous or mucosal, the pseudo-epitheliomatous hyperplasia of the overlying epithelium may, on superficial samples, be mistakenly diagnosed as squamous cell carcinomas. Malignant GCT may, histologically, appear identical to a benign GCT and only the appearance of metastases (generally after local recurrence) permits the subsequent diagnosis of malignancy.

Anal Canal↗
PubMed2003

[Pleuropulmonary blastoma: possible interest of neoadjuvant chemotherapy. A case report].

Pleuropulmonary blastoma is a very exceptional anatomoclinical and histological entity recently distinguished from adult pneumoblastoma. This tumor, observed in children aged less than 15, can involve the lung, the pleura, or the mediastinum and is characterized by a very poor prognosis. We report the case of a 4-year-old girl who developed pleuropulmonary blastoma which was discovered in a context of respiratory distress. Standard chest x-ray revealed an opacity covering the entire left lung. Histology and immunohistology led to the diagnosis of pleuropulmonary blastoma with several components: blastematous, malignant mesenchymatous with pluridirectional differentiation, and benign epithelial tissue. Treatment consisted in preoperative chemotherapy and radiotherapy to reduce tumor volume. This neoadjuvant treatment is not widely reported and its relatively favorable result allowed tumor resection. This approach might be useful in similar cases.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[Nodular fasciitis or pseudosarcoma].

Nodular fasciitis is a benign neoplastic and reactive proliferation of fibroblasts of soft tissues, which is often mistaken for a sarcoma because of its rapid growth, rich cellularity and mitotic activity. A case is reported that provides the opportunity to discuss the specific clinical and pathological features of nodular fasciitis.

Adult↗
PubMed2001

Angiotensin II promotes selective uptake of high density lipoprotein cholesterol esters in bovine adrenal glomerulosa and human adrenocortical carcinoma cells through induction of scavenger receptor class B type I.

Angiotensin II is one of the main physiological regulators of aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex. The hormone stimulates intracellular cholesterol mobilization to the mitochondrion for steroid biosynthesis. Here we have examined whether angiotensin II also modulates exogenous lipoprotein cholesterol ester supply to the steroidogenic machinery and whether this control is exerted on the selective transport of high density lipoprotein-derived cholesterol ester to intracellular lipid droplets through the scavenger receptor class B type I. In bovine adrenal glomerulosa and human NCI H295R adrenocortical carcinoma cells, high density lipoprotein stimulated steroid production. Angiotensin II pretreatment for 24 h potentiated this response. Fluorescence microscopy of cellular uptake of reconstituted high density lipoprotein containing a fluorescent cholesterol ester revealed an initial, time-dependent narrow labeling of the cell membrane followed by an intense accumulation of the fluorescent cholesterol ester within lipid droplets. At all time points, labeling was more pronounced in cells that had been treated for 24 h with angiotensin II. Fluorescence incorporation into cells was prevented by a monoclonal antibody directed against apolipoprotein A-I. Upon quantitative fluorometric determination, cholesterol ester uptake in angiotensin II-treated bovine cells was increased to 175 +/- 15% of controls after 2 h and to 260 +/- 10% after 4 h of exposure to fluorescent high density lipoprotein. The amount of scavenger receptor class B type I protein detected in cells treated with angiotensin II for 24 h reached 203 +/- 12% of that measured in control cells (n = 3, P < 0.01). In contrast, low density lipoprotein receptors were only minimally affected by angiotensin II treatment. This increase in scavenger receptor class B type I protein was associated with a 3-fold induction of scavenger receptor class B type I mRNA, which could be prevented by actinomycin D but not by cycloheximide. Similar results were obtained in the human adenocarcinoma cell line H295R. These observations show that angiotensin II regulates the scavenger receptor class B type I-mediated selective transport of lipoprotein cholesterol ester across the cell membrane as a major source of precursor for mineralocorticoid biosynthesis in both human and bovine adrenal cells.

Adrenal Cortex Neoplasms↗
PubMed2001

Decreased expression of steroidogenic acute regulatory protein: a novel mechanism participating in the leptin-induced inhibition of glucocorticoid biosynthesis.

The adipocyte-derived hormone leptin is a central modulator of food intake, metabolism and neuroendocrine functions. It is also involved in a physiological loop linking the activity of the hypothalamo-pituitary-adrenal axis and adipose tissue. At the adrenal level, leptin has been shown to antagonize the effects of ACTH on glucocorticoid biosynthesis by decreasing the expression of various enzymes of the steroid biosynthetic pathway. The steroidogenic acute regulatory protein regulates cholesterol delivery to the P450(scc) enzyme, a process that is rate limiting in steroid hormone biosynthesis. We have demonstrated here that leptin significantly inhibits the expression of steroidogenic acute regulatory protein in primary cultures of rat adrenocortical cells. This inhibition was observed at both the protein and mRNA levels. In contrast, leptin was not found to interfere with the expression of the cytosolic enzyme cholesterol ester hydrolase or with that of the mitochondrial enzyme P450(scc). In addition, we observed the anticipated stimulation of cAMP production by ACTH in the presence of leptin, suggesting that it does not interfere with intracellular ACTH signaling. In summary, our data provide evidence that the interplay existing between leptin and ACTH in vivo is mediated at least partially via a direct and opposite modulation of steroidogenic acute regulatory protein, a key factor in the adrenal steroid biosynthetic pathway. This effect of leptin could also be relevant to other steroidogenic tissues.

Adrenocorticotropic Hormone↗
PubMed2001

[Rosai-Dorfman disease revealed by renal failure: case report].

We report a case of Rosaï-Dorfman Disease revealed by renal failure in a 43 years old patient. Clinical presentation included abdominal lymphadenopathy and general status deterioration. Diagnosis was established by histopathological examination of the node which revealed sinusal lymphohistiocytosis. Treatment combined prednisone and cyclophosphamide and was effective with regression of renal failure. We will review the diagnostic criteria and the prognosis of this disorder of unknown etiology.

Acute Kidney Injury↗
PubMed1999

[Fibrocartilaginous mesenchymoma of bone. A case report].

Fibrocartilaginous mesenchymoma of bone is a tumoral entity which is somewhat controversial. It has been delineated in 1984 by Dahlin and al. Fifteen cases have been reported in the literature. We report a new case which involves proximal humerus. X-ray data, microscopic findings and local recurrence indicate a low grade malignancy. Metastasis have never been reported. The main differential diagnosis are desmoplastic fibroma, fibrous dysplasia and fibrosarcoma with low grade malignancy. Treatment is surgical.

Adolescent↗
PubMed1998

Transforming growth factor beta1 decreases cholesterol supply to mitochondria via repression of steroidogenic acute regulatory protein expression.

Transforming growth factor-betas (TGF-betas) constitute a family of dimeric proteins that affect growth and differentiation of many cell types. TGF-beta1 has also been proposed to be an autocrine regulator of adrenocortical steroidogenesis, acting mainly by decreasing the expression of cytochrome P450c17. Here, we demonstrate that TGF-beta1 has a second target in bovine adrenocortical cells, namely the steroidogenic acute regulatory protein (StAR). Indeed, supplying cells with steroid precursors revealed that TGF-beta1 inhibited two steps in the steroid synthesis pathway, one prior to pregnenolone production and another corresponding to P450c17. More specifically, TGF-beta1 inhibited pregnenolone production but neither the conversion of 25-hydroxycholesterol to pregnenolone nor P450scc activity. Thus, TGF-beta1 must decrease the cholesterol supply to P450scc. We therefore examined the effect of TGF-beta1 on the expression of StAR, a mitochondrial protein implicated in intramitochondrial cholesterol transport. TGF-beta1 decreased the steady state level of StAR mRNA in a time- and concentration-dependent manner. This inhibition occurs at the level of StAR transcription and depends on RNA and protein synthesis. It is likely that the TGF-beta1-induced decrease of StAR expression that we report here may be expanded to other steroidogenic cells in which a decrease of cholesterol accessibility to P450scc by TGF-beta1 has been hypothesized.

Animals↗
PubMed1998

Atrial natriuretic peptide inhibits calcium-induced steroidogenic acute regulatory protein gene transcription in adrenal glomerulosa cells.

Atrial natriuretic peptide (ANP) is a potent inhibitor of mineralocorticoid synthesis induced in adrenal glomerulosa cells by physiological agonists activating the calcium messenger system, such as angiotensin II (Ang II) and potassium ion (K+). While the role of calcium in mediating Ang II- and K(+)-induced aldosterone production is clearly established, the mechanisms leading to blockade of this steroidogenic response by ANP remain obscure. We have used bovine adrenal zona glomerulosa cells in primary culture, in which an activation of the calcium messenger system was mimicked by a 2-h exposure to an intracellular high-calcium clamp. The effect of ANP was studied on the following parameters of the steroidogenic pathway: 1) pregnenolone and aldosterone production; 2) changes in cytosolic ([Ca2+]c) and mitochondrial ([Ca2+]m) Ca2+ concentrations, as assessed with targeted recombinant aequorin; 3) cholesterol content in outer mitochondrial membranes (OM), contact sites (CS), and inner membranes (IM); 4) steroidogenic acute regulatory (StAR) protein import into mitochondria by Western blot analysis; 5) StAR protein synthesis, as determined by [35S]methionine incorporation, immunoprecipitation, and SDS-PAGE; 6) StAR mRNA levels by Northern blot analysis with a StAR cDNA; 7) StAR gene transcription by nuclear run-on analysis. While clamping Ca2+ at 950 nM raised pregnenolone output 3.5-fold and aldosterone output 3-fold, ANP prevented these responses with an IC50 of 1 nM and a maximal effect of 90% inhibition at 10 nM. In contrast, ANP did not affect the [Ca2+]c or [Ca2+]m changes occurring under Ca2+ clamp or Ang II stimulation in glomerulosa cells. The accumulation of cholesterol content in CS (139.7 +/- 10.7% of control) observed under high-Ca2+ clamp was prevented by 10 nM ANP (92.4 +/- 4% of control). Similarly, while Ca2+ induced a marked accumulation of StAR protein in mitochondria of glomerulosa cells to 218 +/- 44% (n = 3) of controls, the presence of ANP led to a blockade of StAR protein mitochondrial import (113.3 +/- 15.0%). This effect was due to a complete suppression of the increased [35S]methionine incorporation into StAR protein that occurred under Ca2+ clamp (94.5 +/- 12.8% vs. 167.5 +/- 17.3%, n = 3). Furthermore, while the high-Ca2+ clamp significantly increased StAR mRNA levels to 188.5 +/- 8.4 of controls (n = 4), ANP completely prevented this response. Nuclear run-on analysis showed that increases in intracellular Ca2+ resulted in transcriptional induction of the StAR gene and that ANP inhibited this process. These results demonstrate that Ca2+ exerts a transcriptional control on StAR protein expression and that ANP appears to elicit its inhibitory effect on aldosterone biosynthesis by acting as a negative physiological regulator of StAR gene expression.

Aldosterone↗
PubMed1997

Submitochondrial distribution of three key steroidogenic proteins (steroidogenic acute regulatory protein and cytochrome p450scc and 3beta-hydroxysteroid dehydrogenase isomerase enzymes) upon stimulation by intracellular calcium in adrenal glomerulosa cells.

In adrenal glomerulosa cells, angiotensin II (Ang II) and potassium stimulate aldosterone synthesis through activation of the calcium messenger system. The rate-limiting step in steroidogenesis is the transfer of cholesterol to the inner mitochondrial membrane. This transfer is believed to depend upon the presence of the steroidogenic acute regulatory (StAR) protein. The aim of this study was 1) to examine the effect of changes in cytosolic free calcium concentration and of Ang II on intramitochondrial cholesterol and 2) to study the distribution of StAR protein in submitochondrial fractions during activation by Ca2+ and Ang II. To this end, freshly prepared bovine zona glomerulosa cells were submitted to a high cytosolic Ca2+ clamp (600 nM) or stimulated with Ang II (10 nM) for 2 h. Mitochondria were isolated and subfractionated into outer membranes, inner membranes (IM), and contact sites (CS). Stimulation of intact cells with Ca2+ or Ang II led to a marked, cycloheximide-sensitive increase in cholesterol in CS (to 143 +/- 3. 2 and 151.1 +/- 18.1% of controls, respectively) and in IM (to 119 +/- 5.1 and 124.5 +/- 6.5% of controls, respectively). Western blot analysis revealed a cycloheximide-sensitive increase in StAR protein in mitochondrial extracts of Ca2+-clamped glomerulosa cells (to 159 +/- 23% of controls). In submitochondrial fractions, there was a selective accumulation of StAR protein in IM following stimulation with Ca2+ (228 +/- 50%). Similarly, Ang II increased StAR protein in IM, and this effect was prevented by cycloheximide. In contrast, neither Ca2+ nor Ang II had any effect on the submitochondrial distribution of cytochrome P450scc and 3beta-hydroxysteroid dehydrogenase isomerase. The intramitochondrial presence of the latter enzyme was further confirmed by immunogold staining in rat adrenal fasciculata cells and by immunoblot analysis in MA-10 mouse testicular Leydig cells. These findings demonstrate that under acute stimulation with Ca2+-mobilizing agents, newly synthesized StAR protein accumulates in IM after transiting through CS. Moreover, our results suggest that the import of StAR protein into IM may be associated with cholesterol transfer, thus promoting precursor supply to the two first enzymes of the steroidogenic cascade within the mitochondria and thereby activating mineralocorticoid synthesis.

Angiotensin II↗
PubMed1996

Calcium stimulates intramitochondrial cholesterol transfer in bovine adrenal glomerulosa cells.

In adrenal glomerulosa cells, angiotensin II (Ang II) stimulates aldosterone synthesis through rises of cytosolic calcium ([Ca2+]c). The rate-limiting step in this process is the transfer of cholesterol to the inner mitochondrial membrane, where it is converted to pregnenolone by the P450 side chain cleavage enzyme. The aim of the present study was to examine the effect of changes in [Ca2+]c and of Ang II on intramitochondrial cholesterol distribution. Freshly prepared bovine zona glomerulosa cells were submitted to a cytosolic Ca2+ clamp (600 nM) or stimulated with Ang II (10 nM). Mitochondria were isolated and subfractionated into outer membranes (OM), inner membranes (IM), and contact sites (CS). Cholesterol content was determined by the cholesterol oxidase assay. Stimulation of intact cells with Ca2+ led to a marked decrease in cholesterol content of OM (to 54 +/- 24% of controls, n = 5) and to a concomitant increase of cholesterol in CS and IM (to 145 +/- 14%, n = 5). When glomerulosa cells were exposed to Ang II, a marked increase of cholesterol in CS occurred (to 172 +/- 16% of controls, n = 5). No significant changes were detected in OM cholesterol, suggesting a stimulation of cholesterol supply to the mitochondria in response to Ang II. Cycloheximide specifically and significantly reduced Ca2+-activated cholesterol transfer to CS and IM. In conclusion, our data indicate that one of the main functions of the Ca2+ messenger is to increase cholesterol supply to the P450 side chain cleavage enzyme by enhancing endogenous intermembrane cholesterol transfer to a mitochondrial site containing the enzymes responsible for the initial steps of the steroidogenic cascade.

Angiotensin II↗
PubMed1996

Sources and sites of action of calcium in the regulation of aldosterone biosynthesis.

The role of free calcium as a crucial intracellular messenger in the stimulation of aldosterone biosynthesis by various agonists is well established. Using electropermeabilized or Ca(2+)-clamped adrenal zona glomerulosa (ZG) cells, we have previously shown that Ca2+ entry into the mitochondrial matrix is required for the activation of steroidogenesis. We now describe the use of various strategies to answer the following questions: 1. Which pathway does Ca2+ follow before triggering steroidogenesis? 2. Which step of steroidogenesis is under the control of Ca2+? The first approach combined the patch-clamp method, in the perforated patch configuration, with microfluorimetry of Ca2+; in the second approach, ZG cells were transiently transfected with a chimeric cDNA encoding for the calcium-sensitive photoprotein aequorin linked to a mitochondrial targeting presequence; in a third approach, ZG mitochondria were isolated and fractionated into outer membranes, contact sites and inner membranes and the effect of prior exposure of the ZG cells to a physiologically elevated intracellular calcium concentration or to angiotensin II (Ang II) on cholesterol content was then examined in those three mitochondrial fractions. The results of these combined approaches allow us to propose the following scheme: The source of calcium which is predominantly responsible for mediating the steroidogenic effect of potassium appears to be funneled through the T-type calcium channels to close proximity of the mitochondria. This signal, as well as that triggered by Ang II, appears to be relayed within the mitochondrial matrix. This rise of mitochondrial calcium is associated with a transfer of free cholesterol from the outer to the inner mitochondrial membrane, via the contact sites. Thus the main role of the calcium messenger is to promote intramitochondrial cholesterol transfer and supply to the P450scc enzyme.

Aequorin↗
PubMed1995

Organization of 3 beta-hydroxysteroid dehydrogenase/isomerase and cytochrome P450scc into a catalytically active molecular complex in bovine adrenocortical mitochondria.

We have previously reported the co-localization [Cherradi et al., Endocrinology 134 (1994) 1358-1364] of 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta-HSD) and cytochrome P450scc (cyt. P450scc) in the inner membrane and in the intermembrane contact sites of adrenocortical mitochondria. This observation raises the question of a possible functional association between the two proteins. Isolated bovine adrenocortical mitochondria are able to convert cholesterol to progesterone without the need of exogenous cofactors. An association of 3 beta-HSD and cyt. P450scc is observed during the purification of 3 beta-HSD from mitochondria. The behaviour of 3 beta-HSD on a column of Heparin-Sepharose is modified by the presence of cyt. P450scc. Immunoprecipitations from mitochondria with either anti-cyt. P450scc or anti 3 beta-HSD antibodies result in a co-precipitation of the two proteins. Both proteins engaged in these immunocomplexes are catalytically active. The interaction was further demonstrated by the surface plasmon resonance method using purified components. An affinity demonstrated by the surface plasmon resonance method using purified components. An affinity constant of 0.12 microM between 3 beta-HSD and P450scc was obtained. These observations suggest that P450scc and 3 beta-HSD may associate into a molecular complex in the mitochondrial compartment and may constitute a functional steroidogenic unit, thus opening new possibilities in the regulation of the production of progesterone and its flow in the adrenocortical cell.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Characterization of the 3 beta-hydroxysteroid dehydrogenase activity associated with bovine adrenocortical mitochondria.

The enzymatic activity of 3 beta-hydroxysteroid dehydrogenase (3 beta HSD/I) constitutes an essential step in the biosynthesis of active steroid hormones such as progesterone, mineralo- and gluco-corticoids, estrogens, and androgens. Its subcellular localization in steroidogenic tissues is usually considered to be mainly microsomal; however, 3 beta HSD/I activity is also present in mitochondrial preparations. In the present study, the distribution of 3 beta HSD/I in bovine adrenocortical subcellular preparations has been reexamined, and the catalytic properties of the enzyme present in the various cell compartments have been characterized. About 30% of the total 3 beta HSD/I was found to remain tightly associated with highly purified mitochondrial preparations. The preferred substrate of the mitochondrial enzyme was pregnenolone. Examination of submitochondrial preparations revealed that 3 beta HSD/I was associated with both the inner membrane and a particulate fraction that sediments in a density gradient between inner and outer membranes. The specific activity of the enzyme was at its highest in this intermediate density fraction, which exhibited the properties of mitochondrial intermembrane contact sites. Taken together, these observations suggest that these contact sites may represent a supramolecular organization of biological significance in adrenocortical cell steroidogenic functions. Such intermembrane fusion sites would facilitate the access of cholesterol to the inner membrane in which cholesterol side-chain cleavage cytochrome P-450 is located as well as the rapid transformation of its reaction product (i.e. pregnenolone) to progesterone by 3 beta HSD/I. Such a submitochondrial organization opens new possibilities in the understanding of the regulation of adrenocortical differentiated functions.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

Dual subcellular localization of the 3 beta-hydroxysteroid dehydrogenase isomerase: characterization of the mitochondrial enzyme in the bovine adrenal cortex.

The enzyme 3 beta-hydroxysteroid dehydrogenase isomerase (3 beta-HSD/I) is an essential step in the biosynthesis of steroid such as progesterone, mineralo- and gluco-corticoids, estrogens and androgens in steroidogenic tissues. It is considered to be mainly localized in microsomes; however, 3 beta-HSD/I activity has also been described to be associated with mitochondrial preparations. In this study, we examined the subcellular distribution of 3 beta-HSD/I in bovine adrenocortical tissue and we characterized the catalytic properties of the enzyme present in the various cell compartments. About 30% of the total 3 beta-HSD/I activity was found to remain tightly associated with the purified mitochondrial pellet. The 3 beta-HSD/I and 3-ketoreductase activities were found in microsomes as well as in mitochondria. The 3 beta-HSD/I associated with the mitochondrial fraction did not require addition of exogenous NAD+. When the pyridine nucleotide was reduced following addition of substrates of the tricarboxylic acids cycle, the mitochondrial 3 beta-HSD/I activity decreased, suggesting that the enzyme utilizes NAD+ available from the matrix space. By contrast, the microsomal enzyme was inactive in the absence of exogenous NAD+. Submitochondrial fractionation disclosed that 3 beta-HSD/I was associated (i) with the inner membrane and (ii) with a particulate fraction sedimenting in a density gradient between inner and outer membranes. This fraction was characterized as contact sites between the two membranes. 3 beta-HSD/I specific activity was much higher in this fraction than in the inner mitochondrial membrane. Altogether, these observations suggest that these mitochondrial intermembrane contact sites may represent a special organization of functional significance, facilitating both the access of cholesterol to the inner membrane where cytochrome P-450scc is located and the rapid transformation of its product, pregnenolone, to progesterone, through 3 beta-HSD/I activity.

3-Hydroxysteroid Dehydrogenases↗