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Introduction: Mineral trioxide aggregate (MTA) has been used successfully for perforation repair, vital pulpotomies, and direct pulp capping. However, little is known about the interactions between MTA and glass ionomer cement (GIC) in final restorations. In this study, 2 null hypotheses were tested: (1) GIC placement time does not affect the MTA-GIC structural interface and hardness and (2) moisture does not affect the MTA-GIC structural interface and hardness., Methods: Fifty cylinders were half filled with MTA and divided into 5 groups. The other half was filled with resin-modified GIC either immediately after MTA placement or after 1 or 7 days of temporization in the presence or absence of a wet cotton pellet. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope and an electron probe microanalyzer (SEM-EPMA) for interfacial adaptation, gap formation, and elemental analysis. The Vickers hardness numbers of the interfacial MTA were recorded 24 hours after GIC placement and 8 days after MTA placement and analyzed using the analysis of variance test., Results: Hardness testing 24 hours after GIC placement revealed a significant increase in hardness with an increase of temporization time but not with a change of moisture conditions (P < .05). Hardness testing 8 days after MTA placement indicated no significant differences among groups. SEM-EPMA showed interfacial adaptation to improve with temporization time and moisture. Observed changes were limited to the outermost layer of MTA. The 2 null hypotheses were not rejected., Conclusions: GIC can be applied over freshly mixed MTA with minimal effects on the MTA, which seemed to decrease with time., (Copyright © 2012 American Association of Endodontists. All rights reserved.)

Introduction: Capasio is being developed as a new generation of endodontic material with potential use as a root-end filling material. The aim of this study was to compare the ability of Capasio and mineral trioxide aggregate (MTA) to penetrate human dentinal tubules and examine the interaction of Capasio and MTA with a synthetic tissue fluid (STF) and root canal walls in extracted human teeth., Methods: Root-end preparations were filled with Capasio or MTA, allowed to set for 4 weeks in STF, and then sectioned at 1, 2, and 3 mm from resected surface. Depth of penetration was evaluated by using scanning electron microscopy (SEM). Next, Capasio and MTA samples were prepared both in 1-g pellets and in root-end preparations. Samples were placed in STF, allowed to set, and then characterized by using SEM, energy dispersive x-ray analysis (EDXA), and x-ray diffraction (XRD) techniques., Results: Penetration of Capasio into dentinal tubules was observed at all levels. No penetration of MTA into dentinal tubules was observed at any level. Both Capasio and MTA formed apatite crystals in the supernatant, on their exposed surfaces, and in the interfacial layers that were similar in structure and elemental composition when evaluated by using SEM and EDXA. XRD analysis of these crystals corresponds with those reported for hydroxyapatite., Conclusions: When used as a root-end filling material, Capasio is more likely to penetrate dentinal tubules. Both Capasio and MTA promote apatite deposition when exposed to STF., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: This study evaluated the cytotoxicity of GuttaFlow and EndoSequence BC sealers and compared them with AH Plus and Tubli-Seal sealers., Study Design: Samples (0.5 mg) of freshly mixed or set BC, GuttaFlow, AH Plus, and Tubli-Seal sealers were eluted with 300, 600, and 1,000 μL cell culture medium for 24 and 72 hours. L929 cells were seeded into 96-well plates at 3 × 10(4) cells/well and cultured with 100 μL eluate from each eluate group. Cells cultured only with culture medium served as control. After 24 hours' incubation, the cytotoxicity was evaluated by MTT assay. Cell viability was calculated as the percentage of the control group, and the results were analyzed with a one-way analysis of variance., Results: For the freshly mixed sealer, cell viability in the AH Plus group was less than in all of the other 3 sealer groups. The Tubli-Seal sealer group had less cell viability than the EndoSequence BC and GuttaFlow sealer groups. For the set sealer, the Tubli-Seal and AH Plus groups had less cell viability than the EndoSequence BC and GuttaFlow sealer groups. There was no cell viability difference between the EndoSequence BC and GuttaFlow sealer groups in the either freshly mixed or set sealer group., Conclusions: The GuttaFlow and EndoSequence BC sealers have lower cytotoxicity than the AH Plus and Tubli-Seal sealers., (Copyright © 2011 Mosby, Inc. All rights reserved.)

This case report describes apical infection on tooth number 24 that spread to adjacent teeth, resulting in devitalized teeth numbers 23 and 25. The 25-year-old Caucasian female patient was referred to the endodontic resident clinic because of uncontrolled apical infection. Root-end surgery and root-end filling of teeth numbers 23, 24, and 25 were performed. The histopathological diagnosis was a periapical cyst; however, the clinical surgical finding of a purulence-filled bone cavity also revealed a periapical abscess. After root-end surgery and regenerative therapy using Mineral Trioxide Aggregate, Bio-Oss xenograft material, and Bio-Gide resorbable collagen membrane, the patient had no symptoms. Radiographs showed the apical lesion had healed satisfactorily at the 6-month, 1-year, and 2-year follow-ups. The clinical implication of this rare case suggests the importance of standard endodontic diagnostic procedures for pulpal and apical diagnosis, prevention of apical periodontitis exacerbation by reducing bacterial factors, and the effectiveness of healing large bone defects using regenerative materials., (Published by Mosby, Inc.)

Objective: A sequential topical application of calcium and fluoride-phosphate solutions was reported to occlude open dentin tubules, mainly with fluoroapatite precipitates by a rapid ionic reaction, and to be effective at treating dentin hypersensitivity. However, its ability to reduce dentin permeability (Lp) is unknown. The aim of this in vitro study was to evaluate the effect of this treatment on Lp., Methods: Nine extracted human third molars were sectioned transversely to obtain 0.5 mm-thick discs, which were then etched and rinsed. Aqueous solutions of 5% (w/w) disodium phosphate containing 0.3% (w/w) sodium fluoride (A) and 10% (w/w) calcium chloride (B) were prepared. The sequential application of the A&B solutions was repeated three times on each disc, which was then rinsed with distilled water. The Lp of the discs was measured before and after the application using a modified Pashley's fluid flow measuring system. The differences in the Lp values between the conditions before and after the solution applications were analysed using a generalized estimating equation method and paired t-test. Scanning Electron Microscopy (SEM) was used to observe the dentin surfaces., Results: All nine discs consistently indicated reduced Lp following the application of the A&B solutions. There was a significant decrease in the mean Lp [microL/(cm(2) s cm H(2)O)] from baseline (-0.27+/-0.25, p=0.011). Overall, an average decrease of 34% Lp occurred after the application of the A&B solutions. SEM observation indicated that the reaction products covered the entire dentin disc surface., Conclusion: The application of the A&B solutions was effective at reducing the Lp of the dentin discs., (Published by Elsevier Ltd.)

Direct pulp capping is treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. It has been studied as an alternate way to avoid vital pulp extirpation. However, the success rate of pulp capping is much lower than that of vital pulp extirpation. Therefore, direct pulp capping is currently considered controversial by many clinicians. To increase the success rate, a critical need exists to develop new biologically based therapeutics that reduce pulp inflammation, promote the continued formation of new dentin-pulp complex, and restore vitality by stimulating the regrowth of pulpal tissue. Bioengineered anti-inflammatory direct pulp-capping materials, together with adhesive materials for leakage prevention, have great potential to improve the condition of the existing pulp from an inflamed to a noninflamed status and lead to a high rate of long-term success., (Published by Mosby, Inc.)

Aims: Our aim was to evaluate the effect of exercise training (TR) on adipocyte-size-dependent expression of leptin and adiponectin., Main Methods: Male Wistar rats were divided into 2 groups, sedentary control (CR) and TR group, and both monitored for 9weeks. Adipocytes isolated from epididymal, retroperitoneal, and inguinal fat depots were independently separated into 3 fractions of different cell size, and the relationships between adipocyte size and either leptin or adiponectin mRNA were determined by real-time RT-PCR analysis., Key Findings: In epididymal and inguinal adipose tissue, positive relationships between adipocyte size and both leptin and adiponectin mRNA expression were found. Comparison of TR and CR rats showed no significant effect of TR on the slopes of the linear regression lines of correlation between leptin mRNA and adipocyte size in either adipose tissue, whereas the slopes of the regression line of correlation between adipocyte size and adiponectin mRNA were greater in TR group. Leptin levels per milliliter of plasma were significantly lower in TR than CR rats, whereas leptin levels adjusted to the 3 fat depots did not differ. TR did not affect adiponectin levels in plasma, whereas adiponectin levels adjusted to the 3 fat depots were significantly greater in TR than CR group., Significance: TR-induced reduction in leptin mRNA expression was closely associated with smaller adipocyte size. However, TR amplified the adipocyte-size-dependent expression of adiponectin mRNA, suggesting that TR-induced alterations in adiponectin mRNA may also be mediated by factor(s) other than adipocyte size.

This study quantified in vitro the root dentin moisture when 10% formalin (group A), 3% sodium azide (group B), and distilled water (group C) were used as teeth storage media. The root dentin moisture of 66 extracted human mandibular single-rooted teeth was measured at baseline (day 0) and at 1, 3, 7, and 14 days using a digital grain moisture meter. The baseline dentin moisture value was used as covariate in the generalized estimating equation (GEE) analysis. The mean dentin moisture values (%) +/- SD on days 0, 1, 3, 7, and 14 were, respectively: 10.6 +/- 0.64, 14.3 +/- 0.71, 14.6 +/- 0.84, 14.4 +/- 0.64, and 14.7 +/- 0.75 in group A; 11.4 +/- 0.94, 14.6 +/- 0.95, 14.6 +/- 0.76, 14.6 +/- 0.93, and 14.8 +/- 0.81 in group B; and 10.2 +/- 0.95, 12.8 +/- 0.90, 13.3 +/- 0.95, 13.0 +/- 0.91, and 13.2 +/- 0.89 in group C. The dentin moisture increased in all 3 groups; however, there was no overall significant difference in moisture between the formalin and sodium azide groups.

Objectives: To quantify in vitro the root dentin moisture (DM) when soaked in 10% ascorbic acid solution (Group A) and distilled water (Group B) for up to 14 days., Methods: Forty-four extracted human mandibular single-rooted teeth were sectioned perpendicular to the long axis at the CEJ to access the root dentin. The samples were divided into Groups A and B. Baseline (day 0) DM was measured using a digital grain moisture meter. One sample was placed in each tube, which was then filled with solution. All tubes were kept at 37 degrees C and 100% humidity. DM was measured after 1, 3, 7, and 14 days. The baseline DM value was used as a covariate in the generalized estimating equation (GEE) analysis to account for the difference in the baseline DM between the two groups., Results: The mean DM (%) values+/-standard deviation on days 0, 1, 3, 7, and 14 were 11.4+/-1.08, 17.1+/-0.87, 18.2+/-0.76, 18.4+/-0.77, and 17.9+/-0.90 in Group A, and 10.2+/-0.95, 12.8+/-0.90, 13.3+/-0.95, 13.0+/-0.91, and 13.2+/-0.89 in Group B, respectively. Group A had significantly higher baseline DM than Group B (p=0.006). After adjusting for differences in the baseline, the GEE analysis indicated that, on average, Group A had a significantly higher increase in DM than Group B, with means+/-standard deviation of 4.35+/-0.26., Conclusions: The moisture increase in the ascorbic acid group was greater than that in the distilled water group. Soaking root dentin in the unreplenished ascorbic acid solution or distilled water beyond 3 days did not further increase DM.

Dentin moisture content is important in adhesive bonding and structural strength research; however, there is no rapid method available to assess dentin moisture without sample destruction. This study examined the use of a digital grain moisture meter to measure root dentin moisture in vitro. Extracted mandibular single-rooted teeth were sectioned at the CEJ. The moisture of the root dentin was measured at 6 measuring modes for different grains and repeated 5 times. Dentin weight changes before and after drying were measured to obtain control values. The control values were compared with machine readings. In conclusion, (1) each nondestructive measurement took less than 30 seconds, (2) 24 hours of storage at 37 degrees C and 100% humidity did not restore dentin moisture, and (3) 5 grain modes had a high validity and could be used for dentin moisture measurements.

The aim of this study was to examine the particle length, width, perimeter, and aspect ratio of calcium hydroxide powder using a flow particle image analyzer (FPIA). Five sample groups each with 10 mg of calcium hydroxide were mixed with 15 mL of alcohol and sonicated. Digital images of the particle samples were taken using the FPIA and analyzed with a one-way analysis of variance. The overall averages +/- standard deviation among the five groups for particle length (microm), width (microm), perimeter (microm), and aspect ratio were 2.255 +/- 1.994, 1.620 +/- 1.464, 6.699 +/- 5.598, and 0.737 +/- 0.149, respectively. No statistical significance was observed among the groups for all parameters. When the total of 46,818 particles from all five groups were classified into the five length categories of 0.5-microm increments, there were significant differences in width, perimeter, and aspect ratio (all p values <0.0001). In conclusion, calcium hydroxide particles have a size and shape that may allow direct penetration into open dentin tubules.

Aim: To evaluate dentin tubule numerical density variations below the CEJ., Methodology: Three human non-carious permanent canines were sectioned parallel to the CEJ to obtain dentin disks 1mm thick whose surfaces were 1mm and 2mm below the CEJ. Each disk was sectioned into quarters resulting in four segment locations: facial, lingual, mesial, and distal. The outer (PDL side) and inner (pulp side) surfaces of the specimens were shaped to expose dentin with SiC papers and polished. Numerical tubule density was determined from SEM images. All data were statistically analyzed using a three-way ANOVA., Results: The dentin tubule density (number/mm(2)) ranged from 13,700 to 32,300. Dentin tubule density was relatively uniform at 1mm and 2mm below the CEJ and increased by a factor of about two from the outer to the inner surface, which was significantly different (P<0.0001)., Conclusions: The tubule density variations at the cervical root did not present marked.

The aim of this study was to observe particle length, width, perimeter, and aspect ratio of mineral trioxide aggregate finer fractions using Portland cement. The High Power Field mode of the flow particle image analyzer was used for analysis. Images of particle samples were automatically collected by the analyzer along with analysis parameters. Mean, standard deviation, and the number of particles were calculated in each group. Parameters of length, width, and perimeter did not show a statistical significance when groups were compared. Examining the parameter of aspect ratio, there was evidence of a statistical significance seen (p<0.05). The cumulative percentage of particles that were between 0.5 and 3 microm in size was 88%. Fine particles may penetrate dentin tubules. The average aspect ratio was 0.744 (SD=0.155). It can be speculated that a dentin tubule occlusion pattern is dependent on the aspect ratio.

The aim of this study is to characterize the particle size distribution and circularity of various Mineral Trioxide Aggregates (MTA) (ProRoot MTA/ MTA Angelus/Gray and White) and Portland cements with effective size ranges of 1.5-160 microm using a flow particle analyzer (Sysmex FPIA-3000, Kobe, Japan). Cumulative percentage of particles between 6 and 10 microm were, 65, 73, 48, 53, and 70 %, for Gray ProRoot MTA, White ProRoot MTA, Gray MTA Angelus, White MTA Angelus, and Portland cement, respectively. ProRoot MTA contains fewer large particles than MTA Angelus. MTA Angelus contains a higher number of small particles than ProRoot MTA. White MTA contains smaller particles with a narrower range of size distribution than Gray MTA. MTA Angelus particles have relatively low circularity and wide size distribution and are less homogeneous than ProRoot MTA.

There was only one dental school in Malaysia until 1997 but five new schools have been established since 1998. This review provides information about dental education in Malaysia including; the history of dental education, the current dental school system and curriculum, and dental licensure. There are four public and two private dental schools in Malaysia. High school graduates are required to take the nationwide matriculation entrance examination or the Higher School Certificate (HSC) to apply for a dental degree programme. A five-year dental programme leads to the BDS or the DDS degree. National or state examinations are not required to practise dentistry. Currently, there are approximately 2,500 dentists, with a ratio of 1 dentist for every 10,000 people.

Thailand is geographically located in southeast Asia and its population is 63 million. Little has been published on dental education in Thailand. This paper provides information about Thailand regarding its dental history, dental school system including curriculum and dental licensure. There are eight public and one private dental school in Thailand. A six-year dental education leads to the DDS degree. On graduation from the public dental schools, dentists are required to work in the public system for three years. Currently, there are approximately 8000 active dentists, with a dentist: population ratio of approximately 1:7000.

Objective: To explore and describe international oral health attitudes/ behaviours among final year dental students., Methods: Validated translated versions of the Hiroshima University-Dental Behavioural Inventory (HU-DBI) questionnaire were administered to 1,096 final-year dental students in 17 countries. Hierarchical cluster analysis was conducted within the data to detect patterns and groupings., Results: The overall response rate was 72%. The cluster analysis identified two main groups among the countries. Group 1 consisted of twelve countries: one Oceanic (Australia), one Middle-Eastern (Israel), seven European (Northern Ireland, England, Finland, Greece, Germany, Italy, and France) and three Asian (Korea, Thailand and Malaysia) countries. Group 2 consisted of five countries: one South American (Brazil), one European (Belgium) and three Asian (China, Indonesia and Japan) countries. The percentages of 'agree' responses in three HU-DBI questionnaire items were significantly higher in Group 2 than in Group 1. They include: "I worry about the colour of my teeth."; "I have noticed some white sticky deposits on my teeth."; and "I am bothered by the colour of my gums.", Conclusion: Grouping the countries into international clusters yielded useful information for dentistry and dental education.

China is geographically located in the east of Asia and its population exceeds 1.3 billion. An understanding of dental education in China is thus of interest. However, as there is little published information on this topic, this paper provides information about China regarding its dental history, dental school system including curriculum and dental licensure. High school graduates take a nationwide entrance examination to apply for dental school, of which there are more than 50 in China. A five year dental education leads to the BDS degree. Dental school graduates must then pass the nationwide licensure examination to practise dentistry. Currently, there are not adequate numbers of dentists to provide the necessary oral health care for people living outside metropolitan areas.

Objective: To identify similarities and differences in oral health attitudes, behaviour and values among freshman dental students., Design: Cross-cultural survey of dental students., Setting: 18 cultural areas., Participants and Methods: 904 first-year dental students completed the Hiroshima University-Dental Behavioural Inventory (HU-DBI) translated into their own languages. Individual areas were clustered by similarity in responses to the questions., Results: The first group displayed an 'occidental-culture orientation' with the exception of Brazil (Cluster 1 comprised: Australia, United Kingdom, Ireland, Belgium and Brazil, Cluster 2: Germany, Italy, Finland and France). The second group displayed an 'oriental-cultural orientation' with the exception of Greece and Israel (Cluster 3 comprised: China and Indonesia, and Cluster 4: Japan, Korea, Israel, Hong Kong, Malaysia, Thailand and Greece). Australia and United Kingdom were the countries that were most alike. Ireland was the 'neighbour' to these countries. Greece and Malaysia had similar patterns of oral health behaviour although geographic conditions are very different. Although it was considered that in Hong Kong, occidental nations have affected the development of education, it remained in the oriental-culture group. Comparison with the data from the occidentals indicates that a higher percentage of the orientals put off going to the dentist until they have toothache (p < 0.001). Only a small proportion of the occidentals (8%) reported a perception of inevitability in having false teeth, whereas 33% of the orientals held this fatalistic belief (p = 0.001)., Conclusions: Grouping the countries into key cultural orientations and international clusters yielded plausible results, using the HU-DBI.

In recent years, international relationships in dentistry have grown stronger through journals, books, academies, seminars, researcher exchanges and so forth. Korea and Japan are neighbours in East Asia. However, no comparison of the dental education systems of the two countries has been published. Therefore, the authors have provided the present comparison to promote mutual understanding and to familiarise dentists around the world with dental education in these two countries. The number of dentists, life expectancy at birth, and number of decayed, missing, and filled teeth (DMFT) at age 12 years in Korea and Japan are summarised.

The properties of a new, injectable type of root canal wall, adhesive filling resin, which we developed, were studied for its physical properties, adhesiveness to dentin and the root canal, and sealing ability. The new resin consisted of a powder composed of a specially selected poly(methyl methacrylate) and barium sulfate radiopacifier and liquid composed of methyl methacrylate monomer and tributylborane catalyst. A mixture of both components had a consistency suitable for injection. The physical properties, including radiopacity, were evaluated according to the ISO standard. The adhesiveness to dentin and the root canal was investigated by bond strength testing or by scanning electron microscopy. The apical sealing ability of the new resin was compared by a dye penetration test with that of gutta-percha/sealer. The findings of this study indicated that the new filling resin had physical properties satisfying all the ISO requirements for dental root canal sealing materials: a tensile bond strength to dentin of 7.3 MPa, a significantly better sealing ability compared with gutta-percha/sealer, the capability of forming resin tags in dentinal tubules, and removability.

Objective: To compare cross-national differences of dental health behaviour among dental hygiene students., Design: Cross-cultural differences., Setting: United States (USA) and Korea., Subjects and Methods: One hundred and twenty-six dental hygiene students in USA and 246 in Korea were surveyed using the Hiroshima University-Dental Behavioural Inventory (HU-DBI) (in English and Korean versions respectively)., Results: There were considerable differences in oral health behaviour between USA and Korean dental hygiene students. Of great significance were findings that while only a small proportion of the USA students (1%) reported gum bleeding when they brushed their teeth, 37% of the Korean students did so (P<0.001). Furthermore, only 19% of the Korean students had been told by their dentist that they were performing a high level of plaque control, contrasted with 76% of the USA students. Logistic regression model showed that it was possible to distinguish USA students from Korean peers with a probability of more than 90% by using the HU-DBI., Conclusions: There were considerable differences in dental health attitudes/behaviour among dental hygiene students in the two countries. The variation in the favourable attitudes/behaviour toward oral health appeared to reflect the students' clinical training experience in Korea.

Objective: To clarify the differences in dental health attitudes/behaviour among freshman dental students., Design: Cross-cultural differences., Setting: Japan, Hong Kong and West China., Participants and Methods: The original version of the Hiroshima University-Dental Behavioural Inventory (HU-DBI) was written in Japanese. After testing the validity of both English and Chinese versions, the original version of the HU-DBI was administered to 58 freshman Japanese dental students, the English version to 43 Hong Kong Chinese peers and the Chinese version to 39 West Chinese peers., Results: Significant cultural differences were found for 16 items out of 20. The most striking result was that the Japanese students were more likely to have used a dye to see how clean their teeth were, compared to their Chinese peers (P<0.001). The Chinese students were less likely to have a belief that they could clean their teeth well without using toothpaste (P<0.001), whereas higher percentages of the Chinese students worried about having bad breath (P<0.001). A higher percentage of the Hong Kong students reported that they regularly checked their teeth in a mirror than did their West Chinese or Japanese peers (P<0.05)., Conclusions: There were considerable differences in dental health attitudes/behaviour among freshman dental students in the three cultural groups.

Objective: To determine whether any differences existed in dental health behaviour between Japanese and Finnish dental students., Setting: Hiroshima University School of Dentistry and the University of Helsinki., Design: Comparison of cross-cultural differences of self-reported oral health behaviour., Subjects: Dental students, 337 in Japan and 113 in Finland., Method: Subjects were surveyed using the Japanese and Finnish versions of a 20-item questionnaire entitled Hiroshima University--Dental Behavioural Inventory (HU-DBI)., Results: Only 2 per cent of Finnish students reported that they put off going to the dentist until they had toothache, compared to 56 per cent of Japanese students. Similarly, significantly more Japanese students thought that their teeth were getting worse despite their daily brushing, compared to their Finnish peers. The mean HU-DBI score of Year 1 Finnish students was higher than that of their Japanese peers, which suggested a higher level of dental health awareness in Finnish students upon entry into dental school. The mean scores of the Japanese students were lower than those of their Finnish peers until Year 3. The mean scores of Year 5 and Year 6 Japanese students were higher than that of Year 1 students, indicating raised self-care levels influenced by the course in preventive dentistry. The gender difference of the HU-DBI score was not a major feature in either country., Conclusions: Self-reported oral health behaviours seemed to be very different between the two countries, which reflected different culture and/or health education systems of the students.

The role of diacylglycerol in the mechanism of amylase release was investigated in isolated rat pancreatic acinar cells. Carbachol produced a time-dependent and dose-related increase in diacylglycerol production which paralleled the time course of amylase secretion. The addition of atropine to acinar cells pretreated with 100 microM carbachol produced a lag in the fall in diacylglycerol levels, which was preceded by a prompt fall in cytosolic Ca2+ and amylase secretion. A threshold concentration of ionomycin amplified the modest action of dioctanoylglycerol on amylase secretion. Ca2(+)-evoked amylase release elicited by saponin permeabilized acinar cells was markedly enhanced by dioctanoylglycerol. These collective findings support the hypothesis that diacylglycerol alone is not an adequate messenger to mediate pancreatic amylase release, but does serve to modulate the actions of Ca2+.

(-)-Isoproterenol-stimulated adenylate cyclase activities were significantly greater in membranes from exercise-trained male rats than in sedentary male rats. GTP-inhibition of forskolin (10 microM)-stimulated cyclase activities were observed in sedentary membranes, whereas the inhibitory actions of GTP were significantly reduced in membranes from trained rat adipocytes. Treatment of membranes with islet-activating protein, a pertusis toxin, completely abolished the differences in GTP-inhibition of forskolin-stimulated cyclase activities between the two groups. The amounts of the inhibitory regulatory protein (41kDa/40kDa polypeptides) were about 40% less in membranes from trained rats than in sedentary membranes, whereas that of the stimulatory regulatory protein (a 45kDa polypeptide) was equivalent. It is concluded that the enhanced cyclase activities of adipocyte membranes from trained male rats appear to result from, in part, an attenuation of the inhibitory pathway due to a specific decrease in the amount of the inhibitory regulatory proteins.