FGF23 induces left ventricular hypertrophy

What's new in FGF23 research?

FGF23 is a hormone that regulates phosphate and vitamin D metabolism by binding to Klotho-fibroblast growth factor (FGF) receptor complex. Excess actions of FGF23 cause several kinds of hypophosphatemic diseases. The mechanism of overproduction of FGF23 in some of these diseases is becoming clear, whereas it is not yet completely understood. Several specific methods to inhibit FGF23 actions have been reported as candidates for new therapies for these FGF23-related hypophosphatemic diseases. On the other hand, many epidemiological studies indicated the association between high FGF23 levels and several adverse events in cardiovascular system, kidney, bone and mortality. FGF23 was recently shown to induce ventricular hypertrophy in a Klotho-independent manner. However, it is not yet shown whether this Klotho-independent action of FGF23 can explain all the results of epidemiological studies.

Developmental and regional patterns of GAP-43 immunoreactivity in a metamorphosing brain

Growth-associated protein-43 is typically expressed at high levels in the nervous system during development. In adult animals, its expression is lower, but still observable in brain areas showing structural or functional plasticity. We examined patterns of GAP-43 immunoreactivity in the brain of the bullfrog, an animal whose nervous system undergoes considerable reorganization across metamorphic development and retains a strong capacity for plasticity in adulthood. Immunolabeling was mostly diffuse in hatchling tadpoles, but became progressively more discrete as larval development proceeded. In many brain areas, intensity of immunolabel peaked at metamorphic climax, the time of final transition from aquatic to semi-terrestrial life. Changes in intensity of GAP-43 expression in the medial vestibular nucleus, superior olivary nucleus, and torus semicircularis appeared correlated with stage-dependent functional changes in processing auditory stimuli. Immunolabeling in the Purkinje cell layer of the cerebellum and in the cerebellar nucleus was detectable at most developmental time points. Heavy immunolabel was present from early larval stages through the end of climax in the thalamus (ventromedial, anterior, posterior, central nuclei). Immunolabel in the tadpole telencephalon was observed around the lateral ventricles, and in the medial septum and ventral striatum. In postmetamorphic animals, immunoreactivity was confined mainly to the ventricular zones and immediately adjacent cell layers. GAP-43 expression was present in olfactory, auditory and optic cranial nerves throughout larval and postmetamorphic life. The continued expression of GAP-43 in brain nuclei and in cranial nerves throughout development and into adulthood reflects the high regenerative potential of the bullfrog's central nervous system.