RESUMEN
We recently discovered a new role for insulin-like growth factor-I (IGF-I) as a specific and direct stimulator of prolactin (PRL) release in addition to its recognized function as an inhibitor of growth hormone (GH) release and synthesis. Little is known of the mechanisms that transduce the actions of IGF-I on PRL and GH release in vertebrates. The present study was undertaken to determine the cellular pathways that mediate the disparate actions of IGF-I on PRL and GH release in hybrid striped bass (Morone saxatilis X M. chrysops). When regulating cellular function, IGF-I may activate two primary pathways, phosphatidylinositol 3-kinase (PI 3-K) and mitogen-activated protein kinase (MAPK). The specific MAPK inhibitor, PD98059, blocked IGF-I-evoked PRL release as well as GH release inhibition over an 18-20-h incubation. LY294002, a specific PI 3-K inhibitor, overcame IGF-I's inhibition of GH release but was ineffective in blocking PRL release stimulated by IGF-I. These studies suggest IGF-I disparately alters PRL and GH by activating distinct as well as overlapping signaling pathways central for mediating actions of growth factors on secretory activity as well as cell proliferation. These results further support a role for IGF-I as a physiological regulator of PRL and GH.
Asunto(s)
Lubina/fisiología , Hormona del Crecimiento/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Prolactina/metabolismo , Transducción de Señal , Animales , Cromonas/farmacología , Flavonoides/farmacología , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Transducción de Señal/efectos de los fármacos , Sirolimus/farmacologíaRESUMEN
BACKGROUND: A collaborative approach to traditional benchmarking involves the formation of a voluntary network of health care providers that cooperate in carrying out the benchmarking study. THE COLLABORATIVE APPROACH: Collaborative benchmarking involves three phases: Select the benchmarking topic. Decision makers at the sponsoring organization select the benchmarking topic. Establish the benchmarking collaborative. Potential participant organizations are identified and encouraged to join the collaborative. Once the collaborative is formed, project stakeholders are identified, a charter for the study is created, and the project steering committee is established. Conduct the study. A combination of internal and external benchmarking can be used, first conducting the project within the collaborative, then repeating the study either within the industry or across industries. Regardless of the benchmarking type selected, the process follows the Plan-Do-Study-Act cycle. An example of a health care system that is benchmarking the workers' compensation process is used to illustrate the three phases of collaborative benchmarking. A second example, which describes a benchmarking project focused on the admissions process, illustrates the external benchmarking phase. PREREQUISITES AND ACCELERATORS: Four prerequisites for effective benchmarking are leadership commitment, experience with continuous quality improvement, preparation of the organization, and identification of key processes. Organizational capacity for learning, knowledge of the customer and process variation, resource availability, and leadership understanding of benchmarking may each accelerate, or retard, the effective use of collaborative benchmarking.