Open Access. Powered by Scholars. Published by Universities.®
Cell and Developmental Biology Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Cell and Developmental Biology
Short-Term Feedback Regulation Of Camp By Accelerated Degradation In Rat Tissues, Tom W. Gettys, Peter F. Blackmore, J. Bruce Redmon, Stephen J. Beebe, Jackie D. Corbin
Short-Term Feedback Regulation Of Camp By Accelerated Degradation In Rat Tissues, Tom W. Gettys, Peter F. Blackmore, J. Bruce Redmon, Stephen J. Beebe, Jackie D. Corbin
Bioelectrics Publications
A recent study showed that cAMP analogs lowered cAMP levels in rat hepatocytes. The present work demonstrates that cAMP analogs also lowered cAMP in a rapid, concentration-dependent manner in heart and fat cells. In order to determine if the cAMP-dependent protein kinase mediated this effect, techniques were developed to assay the protein kinase activity ratio in hepatocytes treated with cAMP analogs. The activation of protein kinase and phosphorylase in hepatocytes by 8-pClΦS-cAMP (where 8-pClΦS- indicates 8-parachlorothiophenyl-) was concentration-dependent and occurred in parallel to proportionate decreases in cAMP. More than 20% of the cAMP binding sites on the protein kinase were …
Discriminative Insulin Antagonism Of Stimulatory Effects Of Various Camp Analogs On Adipocyte Lipolysis And Hepatocyte Glycogenolysis, Stephen J. Beebe, J. Bruce Redmon, Peter F. Blackmore, Jackie D. Corbin
Discriminative Insulin Antagonism Of Stimulatory Effects Of Various Camp Analogs On Adipocyte Lipolysis And Hepatocyte Glycogenolysis, Stephen J. Beebe, J. Bruce Redmon, Peter F. Blackmore, Jackie D. Corbin
Bioelectrics Publications
Although insulin effectively blocked hormone-stimulated glycerol output in adipocytes or phosphorylase activation in hepatocytes, the inhibitory effect of insulin on cAMP analog-stimulated cells depended on the cAMP analog used. Of the 20 analogs tested in adipocytes and 13 tested in hepatocytes, the effects of about half of them were effectively blocked by insulin, whereas the effects of many of them were not inhibited at all. In order to approach the explanation for this discriminative insulin action, the inhibitory effects of insulin on the responses to the analogs in the intact cells were correlated with the in vitro cAMP analog specificity …
Microheterogeneity Of Type Ii Camp-Dependent Protein Kinase In Various Mammalian Species And Tissues, Alison M. Robinson-Steiner, Stephen J. Beebe, Stephen R. Rannels, Jackie D. Corbin
Microheterogeneity Of Type Ii Camp-Dependent Protein Kinase In Various Mammalian Species And Tissues, Alison M. Robinson-Steiner, Stephen J. Beebe, Stephen R. Rannels, Jackie D. Corbin
Bioelectrics Publications
Excluding autophosphorylated species, at least six forms of the regulatory subunit of type II cAMP-dependent protein kinase (R(II)) from various mammalian tissues were identified by sodium dodecyl sulfate (SDS) gel electrophoresis of purified samples and of crude preparations photoaffinity labeled with 8-azido[32P] cAMP and by gel filtration. After autophosphorylation some heart R(II) forms termed type IIA (bovine, porcine, equine, and dog) shifted to a more slowly migrating band on SDS gels while others termed type IIB (rat, guinea pig, rabbit, and monkey) did not detectably shift. Both subclasses of R(II) exhibited variation in apparent M(r) on SDS gels. Bovine and …
Two Classes Of Camp Analogs Which Are Selective For The Two Different Camp-Binding Sites Of Type Ii Protein Kinase Demonstrate Synergism When Added Together To Intact Adipocytes, Stephen J. Beebe, Rob Holloway, Stephen R. Rannels, Jackie D. Corbin
Two Classes Of Camp Analogs Which Are Selective For The Two Different Camp-Binding Sites Of Type Ii Protein Kinase Demonstrate Synergism When Added Together To Intact Adipocytes, Stephen J. Beebe, Rob Holloway, Stephen R. Rannels, Jackie D. Corbin
Bioelectrics Publications
Twenty-five cyclic nucleotide analogs were tested individually to act as lipolytic agents and to activate adipocyte protein kinase. The lipolytic potency of individual analogs correlated better with their K(a) for protein kinase and their lipophilicity rather than with either parameters alone. Some of the most potent lipolytic analogs had high I50 values for the particulate low K(m) cAMP phosphodiesterase suggesting that their effect was not due to raising endogenous cAMP levels through inhibition of phosphodiesterase. The most potent lipolytic analogs contained a thio moiety at the C-8 or C-6 position. These analogs exhibited concave upward dose-response curves. At high concentrations …