Endocrine Abstracts

Somatotroph pituitary adenomas are characterized by unrestrained hormone secretion and cell proliferation alterations. In those tumors, the only mutation so far unequivocally identified is the gsp oncogene (Gsα protein gain of function mutation). Nethertheless, there is no clear difference in the clinical phenotypes of patients bearing tumor with the gsp oncogene (gsp+) or not (gsp−). In addition, an overexpression of the wild-type Gsα protein has been o...

Somatic mutations of the αs subunit of G proteins were initially reported by Landis and collaborators in 1989 in somatotroph tumors characterized by markedly high cAMP levels. These mutations are localized at two critical sites concerning the intrinsic guanosine triphosphatase activity of the protein leading to a constitutive activation of the adenylyl cyclase. The mutated protein has been named the gsp oncogene. On the other hand, Gsα mRNA level varied among ...

Somatostatin is a ubiquitous neuropeptidic inhibitor of various cellular functions including endocrine and exocrine secretion. Moreover, this peptide may control cell proliferation in normal and tumoral tissues. Somatostatin biological effects are mediated by five subtype of G protein-coupled receptor, sst1 through sst5. The somatostatin analogs have high affinity for sst2 receptor and the success of in vivo peptide therapy is correlated with high levels of sst2 in th...

Somatotroph adenomas are characterized by growth hormone hypersecretion and cell proliferation. We have previously identified crosstalk between the cAMP pathway and the MAPKinases ERK1/2 cascade and shown the central place of the MAPKinases in the control of the pituitary function in GH4C1 somatolactotroph cell line.The spatio-temporal organization of the signalling partners governs signalling fidelity and encodes the specificity of biological responses....

Pituitary tumors are most usual intracranial tumors, displaying hormonal hyper-secretion with in some cases a sustained cell proliferation. The somatotroph adenomas are characterised by a GH hypersecretion. The current treatments are based on somatostatinergic or dopaminergic agonists. Unfortunately, there is steel 50% of patients, which remain insensitive to these treatments. The aim of our work is to find a pharmacological alternative to treat the patients resistant to the c...

Somatotroph adenoma represent 20% of pituitary adenoma. Although often considered as benign, they can induce serious neurological and metabolic complications. GH hypersecretion can be inhibited by somatostatin agonists such as octreotide or lanreotide. However, some GH levels reach normal values in only 50% of treated patiens. The decreased sensitivity to the somatostatin agonists was shown to be related to a lower expression of the sst2 gene.To reverse ...