Endocrine Abstracts

Introduction: Thiazolidinediones (TZDs) are synthetic insulin-sensitizing drugs used in the treatment of type 2 diabetes. They work as agonists of peroxisome proliferator-activated receptor γ (PPARg). TZDs action via PPARg does not exclude independent PPARg-activation effects. Our research group has recently reported that TZDs also execute direct effects implicated in glucose homeostasis. However, its mitochondrial action PPARg-independent has not been fully studied yet.<...

The importance of cell cycle regulation in pituitary biology has been suggested from the fact that many gene-targeted mouse models of cell cycle mutations develop diverse pituitary pathologies. The retinoblastoma protein (pRb)/cyclin-dependent kinase 4 (Cdk4) pathway, one of the major mitogen-sensor routes in the cell, seems to be critical in the control of pituitary cell proliferation. Both inactivation of pRb or hyperactivation of Cdk4 result in pituitary hyperplasias or tum...

Obesity protects from osteoporosis. Bone remodeling and energy metabolism could be regulated by the adipocyte-derived hormone, leptin acting on osteoblasts though hypothalamic pathways. Hypothalamic lesions cause obesity. Since most of these patients are also hypopituitary with low IGF1 which could affect bone metabolism the aim of our study was to investigate whether obesity would protect them from osteoporosis.Three groups of patients were studied: (1)...

Giant prolactinomas are uncommon, with some individual case reports described in the literature, but with few series documenting treatment outcomes. They represent a therapeutic challenge, since restoring normoprolactinemia, eugonadism and reducing tumour size may not be realistic goals. Specific complications may also arise during treatment that change the initial management plans. The authors describe a case of a 28-year-old male with visual impairment and behavioural change...

The RET/GFRa/GDNF system displays a wide distribution in tissues such as nervous system, kidneys, intestine or testis. RET has been implicated in human pathologies. RET is a tyrosine-kinase receptor activated by four ligands GDNF, NTN, ART and PSPN through four co-receptors GFRa1, 2, 3 and 4 respectively. Activation of the receptor leads to cell differentiation or proliferation. Our group has shown that RET is expressed specifically in the somatotrope (GH) adult cell populatio...

Pregnancy is a state of physiological hyperphagia and represents a good model to unravel the mechanisms involved in feeding regulation. The hyperphagia is the main responsible for the positive energy balance in gestation, which is necessary for maintaining maternal energy stores. The presence of high serum leptin levels and hyperphagia during pregnancy is a paradoxical event and reflects a state of leptin resistance. In order to evaluate the mechanisms for hypothalamic leptin ...

Familial acromegaly (FA) is a rare disease with less than 150 cases published. For its diagnosis (FA), two or more cases of acromegaly in the same family and the absence of MEN1 and/or Carney syndrome are required. FA is in the familial isolated pituitary adenomas (FIPA) group although its genetic condition is still under investigation.The index case is an asymptomatic 43-year-old woman with a 4mm pituitary micro-adenoma. There were not acromegaly signs/...

Ghrelin is a pleiotropic hormone characterized mainly by its strong orexigenic action and its role as GH secretagogue.Age-related level variation of this hormone has been previously shown in different studies centred in mARN expression and in its plasma levels; however there is no data about its secretion directly from the stomach although this is the main ghrelin producing organ.Objectives: To determine the levels of ghrelin in th...

Ghrelin, the endogenous ligand for the GH secretagogue receptor type 1a (GHS-R1a), is a peptide with a post-translational octanoyl modification on Ser-3. Previous studies of ghrelin derivatives showed that the pendant group at Ser-3 plays an essential role in the bioactivity. The acylated peptide specifically releases growth hormone (GH) both in vivo and in vitro, while the desoctanoyl form of the hormone is at least 100-fold less potent than the parent peptide.<p class="a...

Treatment for osteoporosis in children/adolescents is extremely important not only to improve bone quality but also because, if left untreated, could lead to severe and precocious loss of bone mass. Studies in growth hormone (GH) deficient adults, in turn, have shown that treatment with GH produce bone mass gain and improve the occurrence of both bone formation and reabsorption.The authors present the following case report of a 16 year old Caucasian fema...