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Philippe J Caron, Antoine P Bennet, Monique M Plantavid and Jean-Pierre Louvet

Caron PJ, Bennet AP, Plantavid MM, Louvet J-P. Luteinizing hormone secretory pattern before and after removal of Leydig cell tumor of the testis. Eur J Endocrinol 1994;131:156–9. ISSN 0804–4643

We studied the luteinizing hormone (LH) secretory pattern in three patients, aged 30, 23 and 43 years, with gynecomastia due to Leydig cell tumor of the testis, before and 6 months after unilateral orchidectomy. The results were compared to those of 11 normal fertile controls aged 20–35 years. Blood sampling was done at 20-min intervals from 22.00 h to 10.00 h. The LH data were analyzed with the Cluster analysis algorithm with "optimal parameters for LH male data" to determine the pulse interval and pulse amplitude. The Expfit program was applied to LH pulses to calculate the apparent half-life of immunoreactive LH. Before surgery, when compared to controls, the patients had a low to normal testosterone/estradiol ratio (0.053, 0.110, 0.046 vs 0.148 ± 0.038) and mean LH levels (1.96, 3.7, 2.55 vs 4.0 ± 1.9 IU/l), decreased pulse amplitude (2.65, 3.01, 2.21 vs 3.31 ± 1.41 IU/l) and reduced apparent half-life of LH (74, 69, 78 vs 97 ± 16 min). After removal of the Leydig cell tumor, the testosterone/estradiol ratio returned to the normal range (0.141, 0.177, 0.093) while an increase in mean LH levels (5.75, 7.90, 4.88 IU/l), LH pulse amplitude (3.07, 6.05, 2.86 IU/l) and apparent half-life of LH (138, 106, 104 min) was observed in all three patients. Our data indicate that endogenous hyperestrogenism in patients with Leydig cell tumor of the testis results in an inhibition of LH secretion, and suggests that such inhibition could result from a reduction in pulse amplitude and apparent half-life.

Philippe Caron, Service d'Endocrinologie et Maladies métaboliques, CHU Rangueil, 1 Avenue J Poulhes, 31054 Toulouse Cedex, France

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Sonia C Dumoulin, Bertrand P Perret, Antoine P Bennet and Philippe J Caron

Dumoulin SC, Perret BP, Bennet AP, Caron PJ. Opposite effects of thyroid hormones on binding proteins for steroid hormones (sex hormone-binding globulin and corticosteroid-binding globulin) in humans. Eur J Endocrinol 1995;132:594–8. ISSN 0804–4643

Sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) levels were evaluated in euthyroid (N = 111), hyper- (N = 58) and hypothyroid (N = 38) men, in pre- and postmenopausal women (study 1) and in hyper- (N = 24) and hypothyroid (N = 15) patients before and after treatment with carbimazole or levothyroxine therapy (study 2). The SHBG levels are increased in hyper- and decreased in hypothyroid patients, whereas CBG levels are increased in hypo- and decreased in hyperthyroid patients. The SHBG levels are higher in women than in men with similar thyroid status. Plasma SHBG levels are correlated positively whereas CBG levels are correlated negatively with free thyroid hormone concentrations in men as well as women. In hypothyroid patients, SHBG concentrations increased (p < 0.01) and CBG concentrations decreased (p < 0.01) during levothyroxine treatment. In hyperthyroid patients, SHBG concentrations decreased (p < 0.01) and CBG concentrations increased (p < 0.01) during antithyroid treatment. The SHBG and CBG concentrations in treated hypo- and hyperthyroid patients were not significantly different from those of euthyroid controls. Our data indicate that SHBG and CBG levels depend on thyroid status. Corticosteroid-binding globulin is an index of thyroid hormone action at the liver level whose changes are opposite to those of SHBG in hyper- and hypothyroidism.

Philippe Caron, Service d'Endocrinologie et Maladies Métaboliques, CHU Rangueil, 1 Avenue J Poulhès, 31054 Toulouse Cedex, France

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Fabrice Bonneville, Louis-David Rivière, Stephan Petersenn, John S Bevan, Aude Houchard, Caroline Sert, Philippe J Caron and the PRIMARYS Study Group

Objective

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.

Design

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.

Methods

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.

Results

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.

Conclusions

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.