It is well known that normal and mildly elevated luteinizing hormone (LH) levels induce increased activity of ovarian 17-hydroxylase and 17,20-lyase, the cytochrome P450cl7alpha (P450) enzymes. This leads to increased ovarian 17alpha-hydroxyprogesterone (17-OHP) and androstenedione production. In contrast, it has been shown in both in vitro and in vivo studies in animals and in in vitro studies in women that high LH concentrations have opposite effects on these enzymes. These LH down-regulating effects appear to be more marked on 17,20-lyase than on 17-hydroxylase. Finally, these LH effects have not been reported in vivo in women. Therefore, we investigated the relationships between serum LH levels and serum 17-OHP and androstenedione concentrations in 263 consecutive hirsute women (HW) with normal serum 17-OHP responses to acute adrenocorticotropin (ACTH) stimulation. The patterns of basal serum steroid concentrations differed according to the basal serum LH levels. Indeed, for relationships between LH and 17-OHP concentrations, a positive correlation (P < 0.001) was found between the levels of these parameters when LH levels ranged from 0.2 to 9.0 IU/l. Conversely, for LH levels greater than 9.0 to 21.0 IU/l, LH values were negatively correlated (P<0.001) with 17-OHP concentrations. Similar results were observed for relationships between LH and androstenedione levels but the LH peak level related to decreasing androstenedione concentrations was 12.0 IU/l. Finally, the mean 17-OHP level in patients with LH levels which induced marked P450 down-regulation (i.e. more than 12 IU/l) was similar to that in patients with LH levels within the normal range (i.e. less than 6 IU/l). In contrast, the mean androstenedione level in the former patients was markedly higher (P<0.001) than that in the latter patients. In conclusion, as previously reported in in vitro studies, this in vivo study indicates that LH induces stimulating and down-regulating effects on both ovarian delta(4)17-hydroxylase and delta(4)17,20-lyase activities as serum LH levels gradually increase. However, in contrast to in vitro studies, LH levels which induce P450 down-regulation appear to be less effective on delta(4)17,20-lyase than on delta(4)17-hydroxylase in HW. This strongly suggests that serum factors induce, in most HW, a marked increase in delta(4)17,20-lyase, but not in delta(4)17-hydroxylase, activity leading to both partial impairment of LH-induced delta(4)17,20-lyase down-regulation and complete LH-induced delta(4)17-hydroxylase down-regulation in these patients.
M Rieu, F Mourrieras, JP Riveline, S Laplanche, D Both and JM Kuhn
P Saugier-Veber, N Drouot, LM Wolf, JM Kuhn, T Frebourg and H Lefebvre
Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is clinically characterized by the presence of two of the three major clinical symptoms: Addison's disease and/or hypoparathyroidism and/or chronic mucocutaneous candidiasis. Because of its autosomal recessive inheritance, this rare disorder constitutes an interesting model for understanding the molecular background of autoimmunity. Recently, mutations in the autoimmune regulator (AIRE-1) gene have been identified in APECED patients. Here we report, in a large French APECED family, the identification of a novel AIRE-1 missense mutation (Pro326Leu) in association with the Arg257Stop mutation which is detected in more than 80% of mutant Finnish AIRE-1 alleles. This Pro326Leu substitution occurs in the first plant homeodomain (PHD)-type zinc-finger domain of the protein which has been identified in a number of nuclear proteins involved in chromatin-mediated transcriptional regulation, such as ATRX, TIF1, KRIP-1 and Mi-2 autoantigen. This mutation highlights the key role of this amino acid in the structure of the PHD domain and confirms that exon 8 constitutes a mutational hotspot.
F Castinetti, M Nagai, H Dufour, J-M Kuhn, I Morange, P Jaquet, B Conte-Devolx, J Regis and T Brue
Objective: Though transsphenoidal surgery remains the first-line treatment of Cushing’s disease, recurrence occurs frequently. Conventional radiotherapy and anticortisolic drugs both have adverse effects. Stereotactic radiosurgery needs to be evaluated more precisely. The aim of this study was to determine long-term hormonal effects and tolerance of gamma knife (GK) radiosurgery in Cushing’s disease.
Design: Forty patients with Cushing’s disease treated by GK were prospectively studied over a decade, with a mean follow-up of 54.7 months. Eleven of them were treated with GK as a primary treatment.
Methods: Radiosurgery was performed at the Department of Functional Neurosurgery of Marseille, France, using the Leksell Gamma Unit B and C models. Median margin dose was 29.5 Gy. Patients were considered in remission if they had normalized 24-h free urinary cortisol and suppression of plasma cortisol after low-dose dexamethasone suppression test.
Results: Seventeen patients (42.5%) were in remission after a mean of 22 months (range 12–48 months). The two groups did not differ in terms of initial hormonal levels. Target volume was significantly higher in uncured than in remission group (909.8 vs 443 mm3, P = 0.038). We found a significant difference between patients who were on or off anticortisolic drugs at the time of GK (20 vs 48% patients in remission respectively, P = 0.02).
Conclusion: With 42% of patients in remission after a median follow-up of 54 months, GK stereotactic radiosurgery, especially as an adjunctive treatment to surgery, may represent an alternative to other therapeutic options in view of their adverse effects.
Fabrice Bonneville, Louis-David Rivière, Stephan Petersenn, John S Bevan, Aude Houchard, Caroline Sert, Philippe J Caron and the PRIMARYS Study Group
Pituitary adenoma MRI T2 signal intensity associates with tumor characteristics including responsiveness to somatostatin analogs (SSAs). These analyses determined whether baseline T2 signal intensity predicts response to primary medical treatment with long-acting SSA.
Post hoc analyses of the prospective multicenter, open-label, single-arm PRIMARYS study in which patients with treatment-naïve GH-secreting pituitary macroadenomas received fixed-dose lanreotide autogel (120 mg) every 4 weeks for 48 weeks.
Associations were investigated between adenoma T2-signal hypo/iso/hyperintensity and treatment responses at week 48/last visit: hormonal control (GH ≤2.5 μg/L and IGF-1 normalization); tumor response (tumor volume reduction (TVR) ≥20%); separate GH/IGF-1 control and change from baseline in GH/IGF-1 and tumor volume.
Adenomas were hypointense at baseline in 50/85 (59%) patients using visual assessment. Of these, 40% achieved hormonal control and 76% achieved a tumor response. Significant univariate associations arose for hypo- vs isointensity with tumor response and achievement of GH ≤2.5 μg/L, but not IGF-1 normalization or overall hormonal control. In multivariate analysis, tumor response was six times more likely for hypo- vs iso-intense tumors (= 6.15; 95% CI: 1.36–27.88). In univariate change-from-baseline analyses, hypo- vs isointensity was associated with greater TVR and IGF-1 reduction but not change in GH. In multivariate analysis, IGF-1 decreased by an estimated additional 65 μg/L (P = 0.0026)) for hypo- vs isointense.
Patients with hypointense vs isointense GH-secreting macroadenomas had greater reductions in IGF-1 following primary treatment with lanreotide autogel and were more likely to achieve tumor response. Assessment of T2 signal intensity at baseline may help to predict long-term responses to primary treatment with SSAs.