RESUMO
The binding characteristics of [3H] alpha-dihydropicrotoxinin to the picrotoxinin binding site were investigated in membrane preparations of adult rat forebrain and living cultures of rat cerebral cortex. The binding of [3H]alpha-dihydropicrotoxinin to rat forebrain was decreased by lysing, treating with Triton X-100, and heating. Coincubation with gamma-aminobutyric acid (GABA), benzodiazepines, or alterations in the Na+ or Cl- composition of the media had no effect on the binding to the rat brain preparation. However, in the living neurons in tissue culture both GABA and diazepam significantly decreased the binding of [3H]alpha-dihydropicrotoxinin. The dose-response relationships for GABA antagonism of [3H]alpha-dihydropicrotoxinin binding and for picrotoxinin antagonism of the GABA enhancement of [3H]flunitrazepam binding in cultured cortical neurons were also investigated. The Hill coefficients for these actions were reciprocal, suggesting that they result from complementary interactions between the binding sites for GABA and picrotoxinin. These data support the association of the picrotoxinin binding site with the postsynaptic GABA receptor complex.
Assuntos
Picrotoxina/análogos & derivados , Receptores de GABA-A/metabolismo , Acetatos/metabolismo , Ácido Acético , Animais , Encéfalo/metabolismo , Cloretos/metabolismo , Diazepam/metabolismo , Relação Dose-Resposta a Droga , Picrotoxina/metabolismo , Ratos , Sesterterpenos , Sódio/metabolismo , Ácido gama-Aminobutírico/metabolismoRESUMO
The effect of long term ascorbic acid (AA) supplementation (3g per day) on 27 women with early breast cancer has been investigated. For comparison a similar but limited study was carried out in patients with benign breast disease. The responses of leucocyte levels of AA to supplementation provided some evidence to suggest that the metabolism and utilisation of the vitamin may be different in these patients. In addition longitudinal measurements of urinary hydroxyproline/creatinine (OHPro/Cr) ratio were carried out in these patients. The long term ingestion of AA did not appear to affect the prognosis of the disease in the early breast cancer group. Similar 5 year survival rates were seen in the unsupplemented and supplemented cancer groups.
Assuntos
Ácido Ascórbico/uso terapêutico , Doenças Mamárias/tratamento farmacológico , Neoplasias da Mama/tratamento farmacológico , Adulto , Idoso , Ácido Ascórbico/sangue , Ácido Ascórbico/metabolismo , Doenças Mamárias/metabolismo , Neoplasias da Mama/metabolismo , Creatinina/urina , Feminino , Humanos , Hidroxiprolina/urina , Estudos Longitudinais , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , PrognósticoAssuntos
Glândula Pineal/análise , Animais , Bovinos , Cromatografia em Gel , Feminino , Hormônio Foliculoestimulante/metabolismo , Hormônio Luteinizante/metabolismo , Melatonina , Ovulação/efeitos dos fármacos , Hipófise/efeitos dos fármacos , Radioimunoensaio , Ratos , Ovinos , Suínos , Hormônio Liberador de Tireotropina/análise , Extratos de Tecidos/análise , Extratos de Tecidos/farmacologia , TrítioAssuntos
Hormônio Liberador de Gonadotropina/fisiologia , Acetilação , Anidridos , Animais , Cromatografia em Papel , Éteres , Formiatos , Hormônio Liberador de Gonadotropina/análise , Hormônio Liberador de Gonadotropina/farmacologia , Histidina , Hipotálamo , Técnicas In Vitro , Maleatos , Azul de Metileno , Oxirredução , Ácido Periódico , Fotoquímica , Hipófise/efeitos dos fármacos , Ratos , Relação Estrutura-Atividade , Suínos , TriptofanoRESUMO
A polypeptide isolated from porcine hypothalami stimulates the release of both luteinizing hormone and follicle-stimulating hormone from the pituitaries of several species. This polypeptide has been structurally identified as (pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH(2) and synthesized. The natural and synthetic materials share biological properties. It appears that this peptide represents the hypothalamic hormone regulating the secretion of both luteinizing hormone and follicle-stimulating hormone.