Assuntos
Bário/farmacologia , Glicóis/farmacologia , Hormônio do Crescimento/metabolismo , Microtúbulos/efeitos dos fármacos , Adeno-Hipófise/efeitos dos fármacos , Hipófise/efeitos dos fármacos , Xantinas/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Bovinos , Colchicina/metabolismo , Glucose/metabolismo , Técnicas In Vitro , Microtúbulos/metabolismo , Adeno-Hipófise/metabolismo , Adeno-Hipófise/ultraestrutura , Tubulina (Proteína)/metabolismoRESUMO
The ionophore A23187 increased the release of rat growth hormone in the presence of a phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine; a second ionophore X537A inhibited growth hormone release induced by the methylxanthine. A23187 did not alter rat growth hormone release in the absence of 3-isobutyl-1-methylxanthine, but X537A enhanced hormone release in the absence of calcium or in the presence or somatostatin. These findings provide further evidence that both calcium and cyclic AMP are important in the regulation of growth hormone release. Tissue incubated in X537A combined electronlucent vesicles apparently derived from the Golgi apparatus, swollen granules and mitochondria with dense matrices. Tissue incubated in the presence of valinomycin or A23187 did not show altered morphology of either secretory granules or the Golgi complex. Possible mechanisms of these changes are discussed.