ISSN:1663-2818    

DOI:10.1159/000181206

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000181207

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000181208

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

This very short review aims at analyzing the current biochemical view of the molecular steps involved in the peptide hormone synthesis, going from the gene to the final active peptide.

ISSN:1663-2818    

DOI:10.1159/000181209

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Secretory proteins follow an intracellular pathway, from their site of synthesis inside the cell to their site of release at the cell surface, within several membrane-bound compartments. Along this route, other exported proteins and membrane proteins travel to their final extracellular or intracellular destination, which implies sorting mechanisms. Morphological observations, performed in our laboratory on normal and tumoral pituitary prolactin cells in culture as well as studies from others on ACTH- and insulin-secreting cells, will be reviewed.

ISSN:1663-2818    

DOI:10.1159/000181231

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The ability of various cofactors to substitute for ascorbate in the biosynthesis of α-aidated peptides from pro-ACTH/endorphin (PAE) was compared in corticotrope tumor cells (AtT-20) and in primary anterior and intermediate pituitary cultures. In all three systems, ascorbate was the most potent cofactor tested. In AtT-20 cells, dopamine, norepinephrine, epinephrine, dehydroascorbate and dihydro- and tetrahydrobiopterin supported significant α-amidation of joining peptide [PAE(77–94)NH2]. In contrast, amidation of joining peptide by primary corticotropes was stimulated only slightly by catecholamines and not by tetrahydrobiopterin. Neither catecholamines nor tetrahydrobiopterin stimulated peptide amidation by melanotropes. The ability of cofactors to support the synthesis of α-amidated peptides is cell-type spec

ISSN:1663-2818    

DOI:10.1159/000181233

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We are interested in the mechanisms by which endocrine and developmental factors regulate TSH synthesis at both pre-translational and post-translational levels. Thyroid hormone profoundly decreases transcription of the TSH-β gene, while TRH and agents modifying cyclic AMP increase transcription. To elucidate the molecular mechanisms underlying these effects, human embryonal kidney cells were transfected with constructs of the human TSH-β gene fused to the chloramphenicol acetyltransferase gene. The first exon of human TSH-β, contains an element that increases basal expression and mediates T3-induced gene repression, probably through a direct interaction with c-erbAβ. This transcriptional repression by T3 appears aberrant in thyrotropic tumors. In contrast, TRH and agents modifying cyclic AMP mediate increased transcription of TSH-β through interacting with upstream regulatory elements. Thyroid hormone, TRH and developmental factors also regulate the branching pattern and relative sialylation of TSH carbohydrate chains, which may affect TSH action in vitro and in vivo. Certain thyrotropic tumors produce TSH with more complex carbohydrate branching patterns, which may increase its biologic acti

ISSN:1663-2818    

DOI:10.1159/000181235

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The ‘two-site’ immunoradiometric assay has been used in a variety of situations to measure and characterize peptides of the hypothalamic pituitary adrenal axis. It has been found that this assay is more sensitive, specific and robust than classical radioimmunoassays and can provide additional evidence of the molecular forms of peptides without resorting to chromatography. The technique can also be used to measure peptides in plasma when a binding protein is pres

ISSN:1663-2818    

DOI:10.1159/000181236

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

As opposed to dominantly-acting oncogenes, antioncogenes represent a new class of tumor suppressor genes, the prototype of which is the gene for retinoblastoma. Hereditary predisposition to cancer can be due to alteration of one copy of an antioncogene, while a tumor will develop only when the second copy is altered by a somatic mutation.

ISSN:1663-2818    

DOI:10.1159/000181238

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Multiple endocrine neoplasia type 2A (MEN2A) is an autosomal-dominant syndrome characterized by medullary thyroid carcinoma (MTC), pheochromocytoma and parathyroid hyperplasia. Recent reports have assigned the locus of MEN2A to the pericentromeric region of chromosome 10. Through the ‘Groupe d’Etude des Tumeurs à Calcitonine’, we have evaluated the ability to predict the carrier state using DNA probes. Our results suggest that the restriction fragment length polymorphism method can be used to identify individuals at risk within MEN2A families. They may then be followed by conventional endocrine methods for the onset of neoplastic changes, limiting the risk of subsequent metastatic disease. The method also permits the exclusion of further screening for family members at very low risk. Extension of the screening program can now be anticipated for other inherited forms of MTC, such as familial MTC without pheochromocytoma or other endocrinological tumor syndromes such as MEN 1 for which the locus has also recently been

ISSN:1663-2818    

DOI:10.1159/000181240

出版商:S. Karger AG    

年代:1989

数据来源: Karger