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K Kariya

Publications and source records attributed to K Kariya.

148 records · Page 9Linked to original sources
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Adrenergic hormones and control of cardiac myocyte growth.

The molecular mechanisms of cardiac myocyte growth are relevant to important problems in cardiovascular disease. A cell culture model has been developed to explore the role of adrenergic hormones in cardiac myocyte growth and gene expression. Activation of a cardiac myocyte alpha 1-adrenergic receptor by catecholamines induces hypertrophic growth of neonatal rat cardiac myocytes and initiates selective increases in contractile protein gene transcription. These effects on growth and gene expression do not depend on contractile activity. The cardiac myocytes contain at least two subtypes of alpha 1-adrenergic receptors and at least three isoforms of protein kinase C (PKC). A distinct alpha 1 receptor subtype may mediate hypertrophy and gene transcription. Different isoforms of PKC are translocated to different intracellular sites on activation, and there is evidence that the beta-PKC isoform may be an element in the signal transduction pathway from an alpha 1 receptor at the surface to the cardiac myocyte nucleus. Growth regulation through a beta-adrenergic receptor can also be demonstrated in the culture model. The growth response mediated through a beta-adrenergic receptor differs in several respects from that transduced through an alpha 1-adrenergic receptor.

Catecholamines↗
PubMedDate not supplied

Alzheimer's disease and estrogen.

The preventive effect of estrogen on Alzheimer's disease (AD) has become clear with epidemiological data. Therapeutic effects of estrogen have not yet been established. In this presentation, we report our new basic and clinical data. The estrogen receptor, (ER)alpha, and ERbeta mRNA were investigated in rat brain. Estradiol-17beta (E(2)) treatment following OVX reduced the levels of ERalpha mRNA in the hypothalamus. In the substantia innominata (SI), the number of choline acetyltransferase immunoreacive cells increased significantly in the estrogen treatment rat. The neurons in SI projecting to the forebrain cortex contained ERalpha. Increasing amounts of intracellular calcium, peroxidation, and apoptosis with amyloid beta were suppressed in neuronal cells from rat pheochromocytoma (PC12) cells with E(2). ERalpha cDNA transfected PC 12 cells elaborated more neurite-like processes with E(2). In clinics, we are currently preparing vaginal progesterone tablets, which essentially may concentrate in the endometrium to prevent endometrial cancer, with few general circulation of progesterone inviting less depression. The therapeutic effects of cyclic estrogen, such as its preventive effect, are suggested in these studies, at least on mild AD.

Alzheimer Disease↗