Genetic regulation of pituitary gland development in human and mouse

Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans

Ein lernender Autopilot mit selbsteinstellender robuster Regelung

This report examines the control of vehicle movement in three-dimensional space. This involves the planning and creation of adapted target trajectories for the control variables and their regulation. The main point of emphasis in the model-assisted multivariable design is in improving the degree of guidance accuracy, taking due account of any uncertainties there may be in the model. The control system comprises two parts: a H_#infinity#robust/H_2-optimum multivariable controller for counteracting unknown sources of interference (feedback control) and a trainable pilot control system using a nonlinear inverse model for achieving the guidance behaviour required (feedforward control). The investigations are simulated taking a submarine as an example. The model of motion for submarines which is generally applied by hydromechanical engineers and which is parameterized in planar motion tests is outlined. Models for actuator and sensor technology are added as they have to be taken into account in the control design. Simplified motion equations also have to be developed which shall provide the basis for all of the other investigations. The investigation is concluded with the results of the simulation for the purposes of assessing the motion control. The investigations described here have their origin in the flight control technology. (orig./AKF)Available from TIB Hannover: H93B2199 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Age in Men Does Not Determine Gonadotropin-Releasing Hormone's Dose-Dependent Stimulation of Luteinizing Hormone Secretion under an Exogenous Testosterone Clamp

Background: Aging is associated with a decline in incremental LH pulse amplitude, which could be due to decreased GnRH secretion or impaired GnRH action

Aerobic Exercise Increases Peripheral and Hepatic Insulin Sensitivity in Sedentary Adolescents

Context: Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents