New variant (Val597Ile) in transmembrane region of the TSH receptor with human chorionic gonadotropin hypersensitivity in familial gestational hyperthyroidism.

OBJECTIVES: Only two mutations at the lysine 183 amino acid in the extracellular N-terminal domain of human TSH receptor (hTSHR) have been associated with hypersensitivity to hCG and familial gestational hyperthyroidism. DESIGN: Describe a new variant of the TSHR gene with hCG hypersensitivity found in two women of the same family diagnosed with gestational hyperthyroidism. PATIENTS: A 38-year-old woman was seen during the first trimester of her second pregnancy for thyrotoxicosis with increased fT3 and fT4 concentrations and low TSH levels without anti-TSH receptor antibody. Thyrotoxicosis improved spontaneously during the 2nd trimester and persisted at the 3rd trimester. Similar clinical symptoms (weight loss, nausea, vomiting) were also reported during the first trimester of her first pregnancy and the first pregnancy of her mother. RESULTS: DNA sequencing of the hTSHR gene of this woman and her mother identifies a heterozygous variant changing valine to isoleucine residue at codon 597 in the transmembrane domain (TMD) of this receptor. In vitro functional studies of this variant showed increased constitutive activity in regard to the basal level of cAMP and IP3 production and to the low cell-surface expression, while response to TSH was reduced compared to that of the wild-type receptor. The Val597Ile variant presented a dose-dependent increase in cAMP response to hGC and human luteinizing hormone (hLH). Simulation of the protein dynamics showed a high structural impact of the Val597Ile variant on helices 3 (TMH3) and 5 (TMH5) of the transmembrane domain participating to constitutive activity and hCG sensitivity. CONCLUSION: We describe a new variant in the transmembrane region of the hTSHR gene with increased constitutive activity and hCG hypersensitivity in familial gestational hyperthyroidism.

Acromegaly and pregnancy: a retrospective multicenter study of 59 pregnancies in 46 women.

CONTEXT: Few data are available on pregnancy outcomes in women with acromegaly. STUDY DESIGN: This was a retrospective multicenter study. PATIENTS: The study included 46 women with GH-secreting pituitary microadenomas (n = 7) or macroadenomas (n = 39). Their mean age was 31.7 yr (±4.5 yr). Incomplete transsphenoidal surgical resection (n = 39) and pituitary radiation (n = 14) had been performed, respectively, 2.9 ± 2.6 and 7.3 ± 4.2 yr before pregnancy. The patients were receiving dopamine agonists (n = 25) and/or somatostatin analogs (n = 14), and GH/IGF-I hypersecretion was controlled and uncontrolled in, respectively, 23 and 34 cases. Five pregnancies followed the fertility treatment. RESULTS: Fifty-nine pregnancies resulted in 64 healthy babies. Gestational diabetes and gravid hypertension occurred in four (6.8%) and eight (13.6%) pregnancies, respectively, and both were more frequent when GH/IGF-I hypersecretion was not controlled before pregnancy. Visual field defects were diagnosed during pregnancy in four women, three of whom were diagnosed with acromegaly during the pregnancy. Seven women had isolated headache. Magnetic resonance imaging performed 3.9 ± 0.3 months after delivery showed that the size of the adenoma had increased in three cases, decreased in two cases, and remained stable in 22 cases. Seventeen women breast-fed with no complications. Four women gave birth to a small-for-gestational-age infant; all had received somatostatin analogs, alone or in combination with dopamine agonists, during pregnancy. The mean IGF-I level fell significantly during the first trimester in 12 cases (before conception 588 ± 207 ng/ml, first trimester 319 ± 126 ng/ml, P = 0.002), whereas the GH concentration did not change significantly. CONCLUSION: The following conclusions were reached: 1) pregnancy in women with active or uncontrolled acromegaly may be associated with an increased risk of gestational diabetes and gravid hypertension; 2) pregnancy is occasionally associated with symptomatic enlargement of GH-secreting pituitary macroadenomas; 3) changes in serum GH and IGF-I concentrations are variable during pregnancy, indicating that routine monitoring is not mandatory if the pregnancy is uneventful; and 4) GH-suppressive treatment can be safely withdrawn after conception in most acromegalic women.

Ectopic Cushing's syndrome due to a pheochromocytoma: a new case in the post-partum and review of literature.

Cushing's syndrome due to AdrenoCorticoTropic Hormone (ACTH)-secreting pheochromocytoma has been rarely reported during pregnancy and post-partum. We report the case of a 30-year-old woman who presented 3 months after delivery acute psychiatric signs and rapid progressive features of Cushing's syndrome. Hormonal tests confirmed ACTH-dependant Cushing's syndrome. A computed tomography scan revealed a 25 x 30 mm tumoral mass in the left adrenal gland and octreoscan scintigraphy showed only an uptake of the radiolabelled octreotide by the adrenal tumor. Fractionated 24-h urinary catecholamines and metanephrines were in the normal range, except for slightly increased adrenalin levels. A left laparoscopic adrenalectomy was performed with acute pulmonary oedema following the anesthesia. Histological examination revealed a 3.5 x 2.5 cm adrenal tumor consistent with a pheochromocytoma without signs of malignancy. The tumor cells immunostained for ACTH and diffuse hyperplasia of adrenocortical cells was observed. After surgery and short stay in intensive care unit, clinical and biological signs rapidly improved and both anti-hypertensive treatment and insulin injections were withdrawn. Genetic testing did not reveal germline mutations in RET protooncogene, Von Hippel Lindau and succinate deshydrogenase genes.

Involvement of cholecystokinin 2 receptor in food intake regulation: hyperphagia and increased fat deposition in cholecystokinin 2 receptor-deficient mice.

The role of cholecystokinin (CCK) as a satiety factor has been extensively documented. Although most work implies that CCK1 receptor mediates the control of food intake, a contributing role for CCK2 receptor (CCK2R) in the CCK-induced satiety cannot be totally excluded. The hypothesis that CCK2R invalidation disrupts regulatory pathways with impact on feeding behavior was examined in CCK2R(-/-) mice. CCK2R(-/-) mice developed obesity that was associated with hyperphagia. Obesity was related with increased fat deposition resulting from adipocyte hypertrophy. Expression of several adipokines was dysregulated consistently with obesity. Moreover, obesity was associated with disturbed glucose homeostasis as revealed by increased fasting glycemia and insulinemia, impaired glucose tolerance, and hepatic insulin resistance in CCK2R(-/-) mice. In vitro analysis of isolated adipocytes metabolism was consistent with increased storage but preserved insulin sensitivity. Suppression of feeding and concomitant increased expression of hypothalamic proopiomelanocortin after intracerebroventricular injection of gastrin into control mice demonstrates that hypothalamic CCK2 receptors mediate inhibition of food intake. Comparative analysis of hypothalamic mediator gene expression in fed knockout and control mice demonstrated overexpression of ghrelin receptors in CCK2R(-/-) mice, indicating up-regulation of orexigenic pathways. This effect was also observed after body weight normalization, indicating a causative role in the development of hyperphagia and obesity of CCK2R(-/-) mice. Our results give evidence that CCK2 receptor activity plays a contributing regulatory role in the control of food intake.