Perilipin, a family of phosphoproteins located around lipid droplets in adipocytes, is essential for enlargement of lipid droplets and lipolytic reaction by hormone-sensitive lipase. Thiazolidinediones, peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been shown to increase perilipin expression in fully differentiated adipocytes. However, the precise mechanism of transcriptional regulation of murine perilipin gene heretofore remains unclear. We determined the transcription start site of murine perilipin gene by RNA ligase-mediated rapid amplification of the cDNA ends method. We generated luciferase reporter gene constructs containing various lengths of the 5'-flanking region of the murine perilipin gene and assayed promoter/enhancer activities using differentiated 3T3-L1 adipocytes. We identified a functional PPAR-responsive element (PPRE) in the murine perilipin promoter, and this was confirmed by gel EMSAs using nuclear extracts from differentiated 3T3-L1 adipocytes. Furthermore, point mutations of the identified functional PPRE markedly reduced both the reporter gene activity in differentiated 3T3-L1 adipocytes and PPARgamma/thiazolidinedione-induced transactivation in NIH-3T3 fibroblasts. Real-time RT-PCR revealed that thiazolidinedione up-regulates endogenous perilipin mRNA levels. We propose that PPARgamma plays a significant role in the transcriptional regulation of murine perilipin gene via the PPRE in its promoter.
Wolfram syndrome is a rare, autosomal recessive disorder characterized by early-onset diabetes mellitus, optic atrophy and neurological and endocrinological abnormalities. A 47-year-old Japanese man with frequent severe hypoglycemic episodes was diagnosed as Wolfram syndrome based on clinical features and laboratory data. He had positive glutamic acid decarboxylase (GAD) and insulinoma-associated antigen-2 (IA-2) antibodies, both uncommon in this syndrome. Genetic analysis revealed that WFS1 gene of the patient has a homozygous 5 base pairs (AAGGC) insertion at position 1279 in exon 8, causing a frameshift at codon 371 leading to premature termination at codon 443
Gitelman's syndrome (GS), an autosomal recessive disorder caused by a defect of the thiazide-sensitive Na-Cl cotransporter (TSC) at the distal tubule, is characterized by hyperreninemic hyperaldosteronism with normal or low blood pressure, hypokalemia, metabolic alkalosis, hypomagnesemia and hypocalciuria. An 18-yr-old Japanese man was admitted to our hospital with a history of muscle weakness and transient tetanic episodes. He showed hypocalcemia in addition to hypokalemia, severe hypomagnesemia, hypocalciuria and hyperreninemic hyperaldosteronism with normal blood pressure. Furthermore, bone mineral density at the lumbar spine revealed osteopenia. A diagnosis of GS was made on the basis of clinical features, laboratory data and renal function test. The electrolyte imbalance was corrected and bone mineral density was slightly increased with chronic treatment of magnesium and potassium salts. Genetic analysis revealed that TSC gene of the patient has a heterozygous C to A nucleotide substitution at position 545 in exon 4, which causes a threonine (Thr) to lysine (Lys) substitution at position 180. This is a rare case of GS with hypocalcemia and osteopenia which could be caused by severe hypomagnesemia.
Hypopituitarism can be caused by tumor, inflammation, granuloma and injuries. Once pituitary function is disturbed, hormone replacement therapy is necessary for the remaining life span in most cases. We have experienced a rare case of a unique intrasellar mass associated with pituitary dysfunction in which both spontaneously reversed. A 61-yr-old woman developed hypoadrenalism and central diabetes insipidus (cDI). Magnetic resonance (MR) imaging revealed a lobular, strong hypointense lesion with spotty signal in the middle of the hypophysis. This spotty lesion showed isointensity on T1- and high-intensity on T2-weighted MR images. The spotty signal as well as the normal pituitary lobe were enhanced by the administration of gadolinium. As replacement therapies for hypoadrenalism and cDI, 10 mg of hydrocortisone and 2.5 microg of desmopressin acetate were prescribed. Three months later, slight shrinkage of intrasellar mass and spontaneous improvement of pituitary functions were found. Hydrocortisone was then discontinued. Furthermore, because polyuria and polydipsia were improved nine months later, desmopressin acetate was stopped. Currently, the intrasellar mass continues to shrink, and the patient shows no symptoms without medication. Based upon the unique features of MR images, we suspect that the origin of the mass is an intrasellar hemangioma.
A 34-year-old Japanese man diagnosed as having cateye syndrome (CES) with isolated idiopathic hypogonadotropic hypogonadism (IHH) was treated at our university. He showed preauricular pits/tags, downward slanting palpebral fissures, ocular hypertelorism, and strabismus. However, ocular coloboma and anal atresia, major characteristic features of CES, were negative. Chromosomal analysis revealed malformation in chromosome 22 and eunuchoid features and a low grade development of secondary sexual characteristics were also evident. Endocrinological examinations revealed that this patient was in a state of isolated IHH. Although CES with IHH is extremely rare, endocrine disorders should be given due attention.
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