{"title":"Insulin release at physiologic potassium concentrations.","authors":"A Hayek","doi":"10.3109/07435808109045743","DOIUrl":"https://doi.org/10.3109/07435808109045743","url":null,"abstract":"<p><p>While high concentrations of potassium directly stimulate pancreatic insulin release, it has not been shown whether potassium ions within the physiologic range produce the same effect. Rats fed a low potassium diet were given KCl intraperitoneally. Insulin levels measured in the portal vein were significantly elevated (172.9 +/- 17 vs 76.5 +/- 14.9 microunits/ml, p less than .05) at 30 minutes, compared to peripheral insulin levels in which the increase did not reach significance. Thus insulin, when measured in portal vein blood samples, is significantly released by potassium increments within the normal range in the absence of exogenous glucose loads.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 4","pages":"247-51"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045743","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18087405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Temporal and quantitative correlations between nuclear androgen binding and stimulation of rna polymerase II activity in Sertoli cells.","authors":"D J Lamb, A Steinberger, B M Sanborn","doi":"10.3109/07435808109045745","DOIUrl":"https://doi.org/10.3109/07435808109045745","url":null,"abstract":"<p><p>The nuclear accumulation of 3H-androgen had been correlated with the effects of this steroid on nuclear RNA polymerase activity in the Sertoli cell under identical experimental conditions. The synthetic androgen methyltrienolone (R1881) was chosen to avoid ambiguities caused by metabolism of the radioligand. Nuclear accumulation of specifically bound 3H-R1881 was apparent after 5 min and preceded RNA polymerase II activation. RNA polymerase II activity was significantly increased by 10 min after administration of R1881, and the response was maximal at 15 min. Although nuclear binding of 3H-R1881 continued to increase over this interval, the enzyme activity declined to basal levels by 20 min. Saturation of nuclear binding sites required concentrations of R1881 that were approximately one order of magnitude higher than those required for maximal polymerase II activation at 15 min. The results indicate that occupancy of only a small fraction of the specific nuclear binding sites by androgen is required to elicit maximal elevation of RNA polymerase II activity in cultured Sertoli cells.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 4","pages":"263-72"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045745","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18027364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Degradation of pork insulin and biosynthetic human insulin in vitro and in vivo: a comparative study.","authors":"P A Halban, W C Duckworth","doi":"10.1080/07435808109049843","DOIUrl":"https://doi.org/10.1080/07435808109049843","url":null,"abstract":"<p><p>The clearance and the degradation of native pork insulin and human insulin prepared by recombinant DNA techniques (biosynthetic human insulin) were compared. Following intravenous injection in rats, biosynthetic human insulin was cleaved slightly more rapidly than pork insulin. Also in vitro, monoiodinated biosynthetic human insulin was degraded slightly more rapidly than pork insulin by the enzyme insulin protease. The apparent Km for pork insulin was 4.0 x 10-8 M and for the human product was 2.7 x 10-8 M. These results thus provide evidence for the integrity of the biosynthetic product.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 2","pages":"127-34"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07435808109049843","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18076339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Properties of triiodothyronine binding sites in cerebral cortical cytosol.","authors":"S E Geel, L Gonzales, P S Timiras","doi":"10.1080/07435808109065979","DOIUrl":"https://doi.org/10.1080/07435808109065979","url":null,"abstract":"<p><p>Some properties of brain cytosol components that specifically bind L-triiodothyronine (T3) were examined in order to resolve their relevance and relationship to nuclear receptors. A marked variation in T3 binding activity was apparent among different brain areas. Binding exhibited temperature dependence and was maximal at 0 degrees C. The binding component was shown to be a protein that migrated as a single included peak on Sephadex G-100 columns at a position corresponding to a Stokes radium of 30A degrees and a M.W. of 54,000. On a linear glycerol gradient the T3-macromolecular complex was estimated to have a sedimentation constant of .4.2S. By combining sedimentation and gel filtration data the calculated M.W. was 53,000. With DEAE-cellulose chromatography the T3 complex eluted as a single peak at 115mM KH2PO4. The results indicate that the properties of the cytosol thyronine-binding protein are similar in many respects to those reported for nuclear receptors. In addition, the regional and developmental binding parameters parallel those for nuclei. We conclude that cytosolic recognition sites may function in the modulation of nuclear receptors and in addition serve to distinguish target from non-target tissue.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 1","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07435808109065979","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17325859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Regulation of cAMP-dissociation kinetics in lactating rat mammary gland.","authors":"F Y Tang, L Catapano","doi":"10.3109/07435808109045739","DOIUrl":"https://doi.org/10.3109/07435808109045739","url":null,"abstract":"<p><p>The cAMP-dissociation kinetics of rat mammary gland cytosols are dependent upon the temperature of cAMP association. Dissociation rates (measured at pH 6.5, 24 degrees C) were biphasic (k = 0.08-0.23 min-1 and k = 0.02 min-1) and monophasic (k-1 = 0.02 min-1) after 0 degrees C and 24 degrees C association, respectively. The temperature-dependent change from an initial fast rate to an initial slow rate was observed at all concentrations of cAMP tested from 1 to 1000 nM. When the slow-dissociating site was associated with non-radioactive 8-bromo-cAMP, the dissociation rates of [3H]-cAMP from the remaining dissociating site was slow (k = 0.02 min-1) and fast (k = 0.05 min-1) at 24 degrees C and 0 degrees C associating rate can be converted to the slow-dissociating rate by warming. When 0.2 M sodium thiocyanate was added to the association mixture at 24 degrees C, biphasic dissociation rates of k = 0.23 min-1 and k = 0.02 min-1 were observed, suggesting that the chaotropic salt blocks the interconversion of rates. The data are consistent with the model for cAMP-dependent protein kinase which exhibits two binding sites with different affinities. The type II enzyme from mammary gland cytosol exhibits in addition the phenomenon of temperature-dependent interconversion of the two binding affinities.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 3","pages":"193-203"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045739","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17339499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of dexamethasone on excretion of urinary kallikrein and urinary protein in Dahl salt-sensitive and salt-resistant rats.","authors":"R P McPartland, J P Rapp, D L Sustarsic","doi":"10.3109/07435808109045735","DOIUrl":"https://doi.org/10.3109/07435808109045735","url":null,"abstract":"<p><p>The effect of glucocorticoid treatment on urinary kallikrein excretion was assessed in Dahl salt-hypertension susceptible (S) and salt-hypertension resistant (R) rats. A single dose of dexamethasone (100 micrograms) caused a marked water diuresis and a slight decrease in urinary kallikrein excretion in both S and R rats. A single dose of dexamethasone also caused the S rat to excrete massive amounts of protein into the urine, almost 3-fold higher than S rats treated with oil; the effect on R rat urinary protein was similar, but less severe. Daily administration of dexamethasone (100 micrograms/day) for 7 days caused marked suppression of urinary kallikrein excretion in both S and R rats. Increased urinary protein following chronic treatment was still evident in the dexamethasone-treated S rats but not in the dexamethasone-treated R rats. Chronic glucocorticoid treatment probably inhibits urinary kallikrein activity by suppressing pituitary and adrenal function which would remove the stimulatory effect of aldosterone on urinary kallikrein excretion. There was no evidence for a stimulatory role of glucocorticoids on urinary kallikrein.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 3","pages":"145-53"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045735","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17963193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Treatment of dopamine-dependent shock with triiodothyronine.","authors":"R D Hesch, M Hüsch, R Ködding, B Höffken, T Meyer","doi":"10.3109/07435808109045741","DOIUrl":"https://doi.org/10.3109/07435808109045741","url":null,"abstract":"<p><p>At the present time dopamine is the most frequently used treatment in patients with septic shock. The effects of dopamine are mediated by alpha-, beta- and dopaminergic receptors. It has been suggested that these receptors are controlled by triiodothyronine (T3). In acute septic shock circulating T3-concentrations are decreased. We have, therefore, treated in a preliminary study 11 such patients with T2-replacement by continuous infusion of T3 (100-200 micrograms/24h). Dopamine dependence was terminated. In all patients there was an increase of arterial blood pressure (BP) within 24 hrs (systolic BP rose by 34 +/- 4.2 mmHg, diastolic BP by 14.0 +/- 8.2 mmHg, resulting in an increase of the mean BP by 25 +/- 6.1 (SEM mmHg). The pulse rate was not influenced suggesting an effect on minute volume. A hypothesis is offered which explains the T3-effects as a result of its decarboxylation to a dopaminergic iodothyronine which is disturbed during the \"low T3-syndrome\".</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 4","pages":"229-37"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045741","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18349874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of peripheral cholinergic activation on the adrenal cortex function.","authors":"M G Kolta, K F Soliman","doi":"10.3109/07435808109045742","DOIUrl":"https://doi.org/10.3109/07435808109045742","url":null,"abstract":"<p><p>The adrenocortical response to cholinergic agonist and antagonist agents were investigated in intact, hypophysectomized and medullectomized rats. The administration of peripherally active compound neostigmine, was found to cause a significant rise of corticosterone in the intact, and the hypophysectomized animals but not in the medullectomized animals. Meanwhile, the centrally and peripherally active cholinergic agent physostigmine caused a significant rise in the intact, hypophysectomized and medullectomized animals. The results also show that the administration of the ganglionic blocker (e.g. tetraethylammonium or hexamethonium), the muscarinic agonist (pilocarpin) or the muscarinic antagonist (atropin) did not result in any significant changes in corticosterone levels. The results of these experiments might indicate that peripheral cholinergic pathway is involved in the regulation of the adrenal cortex function.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 4","pages":"239-46"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045742","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18349875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"In vitro effects of parathyroid hormone on kidney cortical slices: cAMP responses and concomitant inhibition of the Na+ gradient-dependent uptake of phosphate by brush border membrane vesicles isolated from the renal slices.","authors":"L Cheng, C T Liang, B Sacktor","doi":"10.1080/07435808109049841","DOIUrl":"https://doi.org/10.1080/07435808109049841","url":null,"abstract":"<p><p>Mouse renal cortical slices were incubated with parathyroid hormone (30 U/ml) for 2 min. Brush border membrane vesicles isolated from the treated slices had a decreased Na+ gradient-dependent uptake of phosphate. Concomitantly, the hormone elicited the activation of adenylate cyclase, the increase in tissue level of cAMP, and the enhancement of cAMP-dependent protein kinase.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 2","pages":"97-110"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07435808109049841","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17333525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evidence for existence of a serotonin N-acetyltransferase inactivating substance in rat pineal gland.","authors":"A Chan, M Ebadi","doi":"10.3109/07435808109045740","DOIUrl":"https://doi.org/10.3109/07435808109045740","url":null,"abstract":"<p><p>This study provides evidence for the existence of an inactivating substance in pineal glands, which may be responsible for the rapid inactivation of serotonin N-acetyltransferase seen in vivo and in vitro. This serotonin N-acetyltransferase inactivating substance enhances the thermal inactivation of the norepinephrine-stimulated serotonin N-acetyltransferase activity in rat pineal homogenate. Inactivation of serotonin N-acetyltransferase by the inactivating substance and the thermal inactivation of serotonin N-acetyltransferase at 37 degrees C exhibit the following identical properties. Both processes affect serotonin N-acetyltransferase without effect on other melatonin-related enzymes; can be blocked by addition of 0.5 mM [3H] acetyl CoA, but not coenzyme A in the preincubation mixture; and were unaffected by 0.1 M NaF or 4 mM beta-mercaptoethanol. These data are interpreted to suggest that protein dephosphorylation and disulfide exchange mechanisms are not involved in either inactivation processes. Unlike serotonin N-acetyltransferase, which is highly thermo labile, the inactivating substance is thermo stable at 37 degrees C for 40 minutes. In rat, the inactivating substance was found only in the pineal gland and was undetectable in other tissues. The inactivating substance is protein in nature, since it is not dialyzable but is inactivated by boiling or treatment with trypsin. The substance, which was able to inactivate serotonin N-acetyltransferase isolated from rate liver, exhibited no diurnal variation and its activity in rat pineal gland in culture was not influenced by norepinephrine. It is postulated that the interaction among acetyl coenzyme A, serotonin N-acetyltransferase and serotonin N-acetyltransferase inactivating substance may collectively regulate the synthesis of melatonin in pineal gland.</p>","PeriodicalId":75821,"journal":{"name":"Endocrine research communications","volume":"8 3","pages":"205-27"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07435808109045740","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18085541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}