Lutz Vollrath

Johannes Gutenberg University Mainz

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John Fraher

National University of Ireland

Ian Whitmore

Institute of Cancer Research

Stefan Reuss

Johannes Gutenberg University Mainz

P. Semm

Goethe University Frankfurt

Rainer Spessert

University Medical Center of the Johannes Gutenberg University Mainz

Horst A. Welker

Roche (Switzerland)

Francis Knowles

University of California, San Diego

R. Spessert

Johannes Gutenberg University Mainz

André Seidel

University of Bergen

B. Manz

Johannes Gutenberg University Mainz

Cooperative Institutions

Heidelberg University

169

Johannes Gutenberg University Mainz

164

Ludwig-Maximilians-Universität München

Freie Universität Berlin

Czech Academy of Sciences, Institute of Physiology

Max Planck Society

University of Würzburg

University of Tübingen

Goethe University Frankfurt

Medizinische Hochschule Hannover

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CELLULAR PHONES AND HUMAN ENDOCRINE AND IMMUNOLOGICAL AXIS

Epidemiology (1998)

Katja Radon Daekwang Jung David M. Rose D. Parera J Konietzko

Radon, K.; Jung, D.; Rose, D. -M.; Parera, D.; Konietzko, J.; Vollrath, L. Author Information

10.1097/00001648-199807001-00353

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Citations (1)

Proliferation‐associated oxygen consumption and morphology of tumor cells in monolayer and spheroid culture

Journal of Cellular Physiology (1992)

A. Bredel‐Geissler U. Karbach Stefan Walenta Lutz Vollrath W. Mueller‐Klieser

Abstract The oxygen consumption rate, proliferative activity, and morphology of EMT6/Ro mouse mammary sarcoma cells in monolayer and multicellular spheroid culture have been investigated in a comparative study. During the transition of monolayer cells from the exponential into the plateau growth phase, there is a distinct decrease in the cellular volume that is associated with a corresponding decrease in the proliferative and respiratory activity of the cells. The decline in cell volume is mainly due to a decrease in the content of cytoplasm, whereas the size of the nucleus is only slightly reduced. A concomitant decrease in the number of mitochondria per cell obviously accounts for the reduction in cellular oxygen uptake. Despite a continuous decrease of cell proliferation from the surface to interior regions of EMT6 spheroids reflected by a gradient in tritiated thymidine labeling, volume‐related oxygen consumption is rather uniform in viable regions of these aggregates. The finding can be explained by the results of the morphometric evaluation showing a uniform volume density of mitochondria, i.e., of oxygenconsuming sites within these spheroids. © 1992 Wiley‐Liss, Inc.

Spheroid

Morphology

10.1002/jcp.1041530108

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Citations (60)

No short‐term effects of high‐frequency electromagnetic fields on the mammalian pineal gland

Bioelectromagnetics (1997)

Lutz Vollrath R. Spessert Tilman Kratzsch Miriam Keiner H. Hollmann

There is ample experimental evidence that changes of earth-strength static magnetic fields, pulsed magnetic fields, or alternating electric fields (60 Hz) depress the nocturnally enhanced melatonin synthesis of the pineal gland of certain mammals. No data on the effects of high-frequency electromagnetic fields on melatonin synthesis is available. In the present study, exposure to 900 MHz electromagnetic fields [0.1 to 0.6 mW/cm2, approximately 0.06 to 0.36 W/kg specific absorption rate (SAR) in rats and 0.04 W/kg in Djungarian hamsters; both continuous and/or pulsed at 217 Hz, for 15 min to 6 h] at day or night had no notable short-term effect on pineal melatonin synthesis in male and female Sprague-Dawley rats and Djungarian hamsters. Pineal synaptic ribbon profile numbers (studied in rats only) were likewise not affected. The 900 MHz electromagnetic fields, unpulsed or pulsed at 217 Hz, as applied in the present study, have no short-term effect on the mammalian pineal gland.

Specific absorption rate

Extremely low frequency

10.1002/(sici)1521-186x(1997)18:5<376::aid-bem5>3.0.co;2-#

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Citations (42)

Terminologia Embryologica

Lutz Vollrath John Fraher Ian Whitmore

10.1055/b-002-99142

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Citations (17)

Magnetic field effects on pineal N-acetyltransferase activity and melatonin content in the gerbil—role of pigmentation and sex

Physiology & Behavior (1988)

J‐C Stehle Stefan Reuss Heinz C. Schröder Manuela Henschel Lutz Vollrath

Gerbil

10.1016/0031-9384(88)90350-2

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Citations (48)

Adrenoceptor stimulation induces nitric oxide formation in rat pinealocytes

Acta Neurobiologiae Experimentalis (1994)

R. Spessert G. Craig Hill Elisabeth Layes Lutz Vollrath

Pinealocyte

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Citations (2)

[Function of "synaptic ribbons" in the mammalian pineal gland].

PubMed (1974)

Lutz Vollrath

Synaptic membrane

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Citations (1)

Molecular components and mechanism of adrenergic signal transduction in mammalian pineal gland: regulation of melatonin synthesis.

PubMed (2005)

Braj Bansh Prasad Gupta R. Spessert Lutz Vollrath

Rhythmic neural outputs from the hypothalamic suprachiasmatic nucleus (SCN), which programme the rhythmic release of norepinephrine (NE) from intrapineal nerve fibers, regulate circadian rhythm of melatonin synthesis. Increased secretion of NE with the onset of darkness during the first half of night stimulates melatonin synthesis by several folds. NE binds to both alpha1- and beta-adrenergic receptors present on the pinealocyte membrane and initiates adrenergic signal transduction via cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) generating pathways. The NE-induced adrenergic signal transduction switches 'on' melatonin synthesis during the early hours of night by stimulating expression of the rate-limiting enzyme of melatonin synthesis, N-acetyltransferase (AA-NAT) via cAMP-protein kinase A (PKA)-cAMP response element binding protein (CREB)-cAMP response element (CRE) pathway as well as by increasing AA-NAT activity via cAMP-PKA-14-3-3 protein pathway. Simultaneously, adrenergically-induced expression of inducible cAMP early repressor (ICER) negatively regulates aa-nat gene expression and controls the amplitude of melatonin rhythm. In the second half of night, increased release of acetylcholine from central pinealopetal projections, inhibition of NE secretion by SCN, withdrawal of adrenergic inputs and reversal of events that took place in the first half lead to switching 'off' of melatonin synthesis. Adrenergic signal transduction via cGMP-protein kinase G (PKG)-mitogen activated protein kinase (MAPK)-ribosomal S6 kinase (RSK) pathway also seems to be fully functional, but its role in modulation of melatonin synthesis remains unexplored. This article gives a critical review of information available on various components of the adrenergic signal transduction cascades involved in the regulation of melatonin synthesis.

Pinealocyte

Cyclic adenosine monophosphate

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Citations (43)

Musculi; Systema musculare/Muscles; Muscular system

Georg Thieme Verlag eBooks (2013)

Lutz Vollrath John Fraher Ian Whitmore

Muscular system

10.1055/b-0034-99450

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Citations (0)

Pineal Complex of Rats: Effects of Superficial Pinealectomy on the Deep Pineal

Cells Tissues Organs (1983)

U. Heidbüchel Lutz Vollrath

Previous studies have shown that in rodents the pineal complex may consist of two parts, i.e. the small deep pineal and the large superficial pineal. As commonly used techniques of pinealectomy remove the superficial pineal only, it was decided to examine what effect this operation has on the deep pineal in male Sprague-Dawley rats. 3 and 6 weeks after superficial pinealectomy, the deep pineal exhibited a clear decrease in volume, due to an atrophy of the intrinsic pinealocytes. An atrophy was still noticeable after 6 or 12 months. It is concluded that after superficial pinealectomy the deep pineal is not an important factor with respect to melatonin formation, in particular, as there are extrapineal sites of melatonin formation.

Pinealectomy

Pinealocyte

10.1159/000145782

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Citations (9)