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Biomedical subjects

G Schultz

Publications and source records attributed to G Schultz.

At least 307 records · Page 17Linked to original sources
PubMed1981

Na+ amplifies adenosine receptor-mediated inhibition of adipocyte adenylate cyclase.

Membrane preparations of hamster adipocytes were used to study the inhibition of adenylate cyclase by the adenosine analogue, N6-phenylisopropyladenosine (PIA). Inhibition by PIA was half-maximal and maximal (about 40%) at about 0.03 and 1 micro M, respectively, and was antagonized by 3-isobutyl-1-methylxanthine in a competitive manner. Like other hormone receptor-mediated inhibitions of the adipocyte adenylate cyclase, the adenosine receptor-mediated action on the enzyme was absolutely dependent on GTP and was amplified by sodium ions.

1-Methyl-3-isobutylxanthine↗
PubMed1981

[Value of complex methods of evaluating microclimatic conditions].

The authors have checked the correctness and accuracy of the total index of microclimate evaluation, using an analog calculator to process the measurements. Information on the measurements of climate was analysed basing on the total index of climate evaluation qtr, Predicted -- 4 -- Hour -- Sweat -- Rate P4SR, Index of Thermal Stress ITS, Wet Bulb Globe Temperature WBGT, Globe -- Temperature tg, Heat Stress Index HSI, Humid Operative Temperature toH and Effective Temperature ET. In addition, under standard conditions, with differentiated degree of physical effort, the following physiological parameters have been determined in 37 subjects: heart rate, internal body temperature, skin temperature and sweat loss. The obtained data have undergone regression and correlation analysis, stating, among others, that the index of climate evaluation qtr and P4SR -- Index correlate best with all physiological parameters.

Body Temperature↗
PubMed1980

[Action principles of hormones and neurotransmitters (author's transl)].

Membrane-bound receptors for hormones and neurotransmitters can be coupled to other membrane components which generate intracellular signals triggering the cellular response to the hormonal stimulus. For various hormonal factors, the occurrence of receptor subclasses has been established which are bound to different cellular signal-generating systems. Whereas one group of receptors (e.g., beta-adrenergic ones) is linked to adenylate cyclase in a stimulatory manner, other receptors (e.g., alpha 2-adrenergic ones) are linked to this enzyme in an inhibitory manner, and a third group (e.g., alpha 1-adrenergic receptors) is linked to changes in phosphatidylinositol metabolism, calcium distribution and cyclic GMP metabolism. It is not clear whether one given receptor can be linked only to one signal-generating system or whether one type of receptor can be linked to two different signal systems in one cell.

Animals↗
PubMed1980

[Regulation of cellular functions of protein phosphorylation (author's transl)].

The biochemical mechanisms involved in the regulation of cellular functions by intracellular signals, such as calcium, cyclic AMP and cyclic GMP, are described briefly. Each cyclic nucleotide regulated diverse cellular functions by activating a specific protein kinase. Calcium, on the other hand, has several intracellular receptors, i. e., troponin-C, calmodulin and others, which may be present together in the same cell. In the presence of calcium, calmodulin activates a variety of enzymes including protein kinases, phosphorylase kinase and myosin light chain kinase. The specificity of hormonal effects in different tissues depends not only on the presence of the specific intracellular receptor system for each intracellular signal but also on the presence of specific isoenzymic forms of important regulatory enzymes, whose activity may or may not be regulated by phosphorylation and dephosphorylation.

Calcium↗