Assuntos
Proteínas de Drosophila , Neoplasia Endócrina Múltipla Tipo 2b/diagnóstico , Neoplasias das Glândulas Suprarrenais/diagnóstico por imagem , Neoplasias das Glândulas Suprarrenais/cirurgia , Adrenalectomia , Adulto , Cromossomos Humanos Par 10/genética , Códon/genética , Feminino , Humanos , Neoplasia Endócrina Múltipla Tipo 2b/diagnóstico por imagem , Neoplasia Endócrina Múltipla Tipo 2b/genética , Mutação/genética , Feocromocitoma/diagnóstico por imagem , Feocromocitoma/cirurgia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-ret , Receptores Proteína Tirosina Quinases/genética , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Tomografia Computadorizada por Raios XRESUMO
In situ hybridization and immunocytochemical techniques have been used to examine the distribution of vitamin-D-induced calbindin mRNA and calbindin protein in enterocytes lining the crypts and villi of chicken small intestine. Basal villus enterocytes contained approximately twice as much calbindin but over three times as much calbindin mRNA compared to values found in basal crypt and upper villus enterocytes, all values being measured 2 days after vitamin D injection into D-deficient chickens. Virtually no calbindin mRNA was detected in tissues taken from control D-deficient birds. Direct proportionality found between calbindin mRNA and calbindin content in enterocytes of basal crypt, mid and upper villus suggests pre-translational control over calbindin synthesis. The implications of possible inefficient translation of calbindin mRNA in basal villus enterocytes are discussed. Present methods of analysis provide a novel way to study mechanisms controlling gene expression throughout the whole process of enterocyte differentiation.
Assuntos
Expressão Gênica/efeitos dos fármacos , Jejuno/citologia , Proteína G de Ligação ao Cálcio S100/análise , Vitamina D/farmacologia , Animais , Calbindinas , Diferenciação Celular/genética , Galinhas , Densitometria , Feminino , Imuno-Histoquímica , Jejuno/química , Masculino , Hibridização de Ácido Nucleico , RNA Mensageiro/análise , Proteína G de Ligação ao Cálcio S100/genéticaRESUMO
The location of intestinal cells taken from the base of the crypt to the tip of the villus responsive to calcitriol (1,25-dihydroxycholecalciferol) and the distribution of [3H]calcitriol within the intestinal epithelium has been determined in vitamin D-deficient rats. The calcitriol responses examined were CaBP (Ca2+-binding protein) levels as measured by immunodiffusion and alkaline phosphatase levels as determined cytochemically. Calcitriol had no effect on villus structure or on enterocyte kinetics. This made it possible to compare levels of CaBP and alkaline phosphatase activity in enterocytes at different ages in rats at known times after hormone injection. Cells from both the crypt and villus synthesized CaBP in response to calcitriol. Alkaline phosphatase activity was not detectable in crypt cells, although a pool of precursor was produced in these cells in response to calcitriol. Enzyme activity was increased in all villus cells in response to calcitriol, but the quantitative description of this effect was very different from that found for calcitriol effects on CaBP synthesis. Calcitriol injected into vitamin D-deficient rats was detected, within 2h, in all cells of the crypt and villus. Most of the binding was to sites having a high affinity for the injected hormone.
