RESUMEN
Mature male beagles were used in studies designed to determine the effect of the steroidal 5 alpha-reductase inhibitor 17 beta-N,N-diethylcarbamoyl-4-aza-4-methyl-5 alpha-androstan-3-one (4-MA) on size, histology, and androgen concentration of the prostate. Subcutaneous administration of 3 or 15 mg/kg/day for 43 days caused a sharp decline in prostate volume. flattening of prostatic epithelial cells, vacuolization of the cytoplasm and pycnosis of the nuclei. Whereas serum testosterone levels remained normal in dogs injected with 3 mg/kg/day, they were lower in those that received 15 mg/kg/day. Concentration of both testosterone and 5 alpha-dihydrotestosterone were reduced in the prostates of dogs that had received either 3 or 15 mg/kg/day of 4-MA. The 15 mg/kg/day level also appeared to adversely affect spermatogenesis. In a 43-day study, 4-MA given orally once each day at levels of 0.1, 0.3, or 1 mg/kg failed to cause a significant decrease in prostate volume. However, daily divided oral doses totaling 1 or 3 mg/kg were given in a 42-day test and both treatment levels produced significant reductions in prostate size.
Asunto(s)
Inhibidores de 5-alfa-Reductasa , Azaesteroides/farmacología , Dihidrotestosterona/análogos & derivados , Dihidrotestosterona/análisis , Oxidorreductasas/antagonistas & inhibidores , Próstata/efectos de los fármacos , Esteroides Heterocíclicos/farmacología , Testosterona/análisis , Animales , Atrofia/inducido químicamente , Dihidrotestosterona/farmacología , Perros , Relación Dosis-Respuesta a Droga , Masculino , Tamaño de los Órganos/efectos de los fármacos , Próstata/patología , Espermatogénesis/efectos de los fármacosRESUMEN
A number of alkyl, aryl, and aralkyl glycosides (mono- and disaccharides) substituted in the aglycon with a primary amino group have been found to exert insulin-like activity on rat adipocytes in vitro. Systematic variations in the saccharide configuration, glycosidic linkage, aglycon moiety, and sugar substitution pattern were investigated to delineate structure-activity relationships. A high degree of structural specificity was observed. Maximal insulin mimicking activity was obtained with the 6-aminohexyl 1-thio-D-mannopyranosides; the beta anomer was more active than the alpha anomer. Modification of the sugar hydroxyl groups resulted, in most cases, in partial or complete loss of biological activity at the levels tested; however, in a few instances, sugar-modified derivatives did show enhanced insulin-like effects. Specific structural types evaluated are discussed in greater detail. 6-Aminohexyl 1-thio-beta-D-mannopyramoside also exhibited in vivo insulin-like effects on both diaphragm muscle and omental adipose tissues. The specificities for the sugar as well as the aglycon portions of these carbohydrate derivatives suggest that both parts of the molecule are involved in the expression of the full biological activity observed; their respective roles in the mechanism of the insulin-like activity are discussed.
Asunto(s)
Glicósidos/síntesis química , Insulina , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/metabolismo , Animales , Femenino , Glucosa/metabolismo , Glucógeno/biosíntesis , Glicósidos/farmacología , Técnicas In Vitro , Insulina/farmacología , Lípidos/biosíntesis , Masculino , Conformación Molecular , Oxidación-Reducción , Ratas , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
A model for a biologically active conformation of somatostatin is proposed. This model is based primarily on the biological results obtained with novel bicyclic somatostatin analogs having a covalent bridge replacing the side chains of residues 5 and 10, 6 and 11, and 5 and 12, respectively, rather than on physical measurements on the hormone in solution. The high activity of an analog in which Phe6 and Phe11 are replaced by cystine provides evidence that these phenylalanines stabilize the biologically active conformer through "hydrophobic bonding" but do not directly interact with the receptor. The synthesis of the novel bicyclic analogs of somatostatin and the effects of these on the inhibition of secretion of insulin, glucagon, growth hormone, and gastric acid are described.