Apoptotic effect of 5-fluorouracil-doxorubicin combination on colorectal cancer cell monolayers and spheroids

BACKGROUND

Drug combination studies help to improve new treatment approaches for colon cancer. Tumor spheroids (3D) are better models than traditional 2-dimensional cultures (2D) to evaluate cellular responses to chemotherapy drugs. The cultivation of cancer cells in 2D and 3D cultures affects the apoptotic process, which is a major factor influencing the response of cancer cells to chemotherapeutic drugs. In this study, the antiproliferative effects of 5-fluorouracil (5-FU) and doxorubicin (DOX) were investigated separately and in combination using 2D and 3D cell culture models on two different colon cancer cell lines, HT-29 (apoptosis-resistant cells) and Caco-2 2 (apoptosis-susceptible cells).

METHODS

The effect of the drugs on the proliferation of both colon cancer cells was determined by performing an MTT assay in 2D culture. The apoptotic effect of 5-FU and DOX, both as single agents and in combination, was assessed in 2D and 3D cultures through quantitative real-time polymerase chain reaction analysis. The expression of apoptotic genes, such as caspases, p53, Bax, and Bcl-2, was quantified.

RESULTS

It was found that the mRNA expression of proapoptotic genes was significantly upregulated, whereas the mRNA expression of the antiapoptotic Bcl-2 gene was significantly downregulated in both colon cancer models treated with 5-FU, DOX, and 5-FU + DOX.

CONCLUSION

The results indicated that the 5-FU + DOX combination therapy induces apoptosis and renders 5-FU and DOX more effective at lower concentrations compared to their alone use. This study reveals promising results in reducing the potential side effects of treatment by enabling the use of lower drug doses.

Isolation of phenolic compounds from eco-friendly white bee propolis: Antioxidant, wound-healing, and anti-Alzheimer effects

This study presents the first findings regarding extraction, isolation, enzyme inhibition, and antioxidant activity. The oral mucosal wound-healing process was investigated using propolis water extract (PWE) incubation with gingival fibroblast cells and concluded that propolis was effective on the oral mucosal wound-healing pattern compared to untreated controls. Additionally, phenolic compounds (fraxetin, apigenin, galangin, pinobanksin, chrysin, etc.) were isolated from propolis, and their chemical structures were elucidated using comprehensive spectroscopic methods. The antioxidant and anti-Alzheimer potential activities of PWE and some isolated compounds were screened and revealing their inhibitory effects on acetylcholinesterase (AChE) with IC50 values ranging from 0.45 ± 0.01 to 1.15 ± 0.03 mM, as well as remarkable free-radical scavenging and metal reduction capacities. The results suggest that these compounds and PWE can be used as therapeutic agents due to their antioxidant properties and inhibitory potential on AChE. It can also be used for therapeutic purposes since its wound-healing effect is promising.

Biological Screening of Polyphenol Derivatives for Anti-Proliferative, Anti-Apoptotic and Anti-Migrative Activities in Human Breast Cancer Cell Lines MCF-7

Breast cancer is known as the most common type of invasive cancer in women. It is well-known that phenolic compounds play an important role in the treatment of this disease. This study hypothesized that isoeugenol based two polyphenolic compounds 1 and 2 exerts its anti-proliferative effects through the induction of apoptosis and cell migration arrest on human breast cancer cell. Based on this hypothesis, the study aimed to investigate the anti-proliferative, anti-migrative effects of these compounds and their possible basic molecular mechanisms of action in MCF-7 cell lines. As a result, isoeugenol-based compounds 1 and 2 showed anti-proliferative, anti-apoptotic and anti-migrative effects in MCF-7 breast cancer cells. This result was supported by molecular analyzes and it was determined that there were changes in the expression of some gene regions involved in apoptosis and migration. Additionally, it was a remarkable result that cell viability inhibition did not occur in healthy breast tissue cells and no cytotoxic effect was observed. The existence of such a differentiation between cancer cells and healthy cells significantly increases the potential of these compounds to be used as chemotherapeutic drug active ingredients without side effects.

The effect of vitamin D and melatonin on the ocular tissues in streptozotocin - Induced diabetes model in rats

OBJECTIVE

The aim of the study was to investigate the effectiveness of vitamin D and melatonin on the ocular tissues in streptozotocin (STZ)-induced diabetes.

MATERIALS AND METHODS

In this study, a total of 45 male Wistar rats were randomly divided into five groups as follows: 1) non-diabetic rats (control group); 2) untreated STZ-induced diabetic rats; 3) STZ-induced diabetic rats treated with vitamin D; 4) STZ-induced diabetic rats treated with melatonin; 5) STZ-induced diabetic rats treated with the combination of vitamin D and melatonin. After six weeks of treatment, all rats were sacrificed for post-mortem analyses. Retinal and corneal samples were obtained and analyzed for glial fibrillary acidic protein (GFAP) expression. Retinal and corneal thicknesses in addition to morphological changes were assessed via hematoxylin and eosin staining.

RESULTS

Untreated diabetic rats revealed retinal disorganization, atrophy, increased vascularization along with more GFAP staining. However, all the treated groups exhibited more regular retinal layers and minimal GFAP staining. Additionally, treatment groups showed more uniform corneal layers with minimal GFAP staining.

CONCLUSIONS

Melatonin and vitamin D could be used as an additional complementary treatment in diabetes. Developing treatment protocols involving supplementation, as well as informing patients about the potential benefits of vitamin D and melatonin could be impactful in the treatment process of diabetes.

Antiproliferative and Antimigratory Effects of Isoeugenol-Based Polyphenolic Compounds

In this research, the effect of synthesized polyphenolic compounds 4 and 5 at the cellular and molecular levels was examined. Within this framework, related substances effects on prostate cell (PC3) viability were evaluated by MTT analysis, and their effects on migration were examined by in vitro scratch analysis. Additionally, mRNA expression levels of gene regions known to be associated with metastasis and apoptosis were determined by real-time quantitative PCR. DNA binding researches have also been carried out to determine the DNA compound interactions. As a consequence, it was determined that 4 and 5 obstructed the PC3 cell viability in a manner that is dose- and time-dependent. The IC₅₀ dose of 4 and 5 in PC3 cell was found to be 60.14 μM, 15.51 μM for 48 h, respectively. 4 and 5 substances showed suppressive effect on migration of PC3 cancer cells in the in vitro scratch model created at IC₅₀ concentrations. Compared to the negative control, PC3 cancer cells treated with 4 and 5 showed 24 % and 46 % closure, respectively, at the wound site at 48 h. 4 and 5 compounds were treated at IC₅₀ concentrations with PC3 cancer cells for 48 h, and then the effects of both compounds on the gene expression, that have been linked to metastasis and apoptosis, at the mRNA level were evaluated. It was determined that 4 decreased the expression of the HIF1-α gene 294 times and 5 decreased the expression of the said gene 30 times. In addition, both 4 and 5 were able to significantly increase the Bax/Bcl-2 mRNA expression ratio (32.65 and 10.46 fold, P<0.0001) in PC3 cells as compared to untreated cells after 48 h. Finally, when DNA binding analysis results were evaluated, it was determined that both polyphenolic compounds did not bind to DNA at the tested time and concentrations and did not cause DNA breaks.

Does mean platelet volume/lymphocyte count ratio associate with frailty in type 2 diabetes mellitus?

OBJECTIVES

Frailty is a common problem in patients with type 2 diabetes mellitus (T2DM). It is considered to be associated with inflammation. Novel markers derived from hemogram, such as neutrophil/lymphocyte ratio (NLR) and mean platelet volume/lymphocyte ratio (MPVLR), are proposed as inflammatory markers. In present study, we aimed to compare NLR and MPVLR levels of frail patients with T2DM to non‑frail diabetic subjects.

METHODS

Diabetic subjects were grouped in frail and non-frail groups according to the Edmonton Frail Scale. General characteristics and laboratory data of the frail and non-frail groups were compared.

RESULTS

The MPVLR of the frail (3.9 [1.4-13.2] %) group was significantly higher than that of the non-frail (3.4 [1.5-6.9] %) group (p = 0.02). MPVLR was positively and significantly correlated with Edmonton Frail Scale score (r = 0.21, p = 0.03). A MPVLR level greater than 3.41 % has 71 % sensitivity and 51 % specifity in predicting frailty.

CONCLUSION

We suggest that elevated MPVLR could be a finding that marks frailty in diabetic subjects. Inexpensive and easy‑to‑assess nature of the MPVLR may be useful in predicting frailty in type 2 diabetic population (Tab. 2, Fig. 1, Ref. 32).

THE ASSOCIATION BETWEEN VITAMIN D LEVELS AND HANDGRIP STRENGTH IN ELDERLY MEN

Context

Vitamin D is a steroid hormone that acts by binding to the vitamin D receptor (VDR) found in many tissues. According to the long-term mechanism, vitamin D causes the proliferation and differentiation of muscle cells by gene transcription.

Objective

We aimed to evaluate the relationship between muscle strength and serum vitamin D levels in elderly men.

Design

Cross-sectional study.

Subjects and Methods

Male patients over age 50 were included in the study. Study population was divided into 2 groups with handgrip strength according to body mass index, either as subjects with weak or with normal handgrip strength test (HGST). Vitamin D levels and other variables compared between weak and normal groups.

Results

Vitamin D level of weak and normal groups were 7.5 (3-19.9) μg/L, and 11.6 (11.6-34.9) μg/L, which means significant reduced vitamin D levels in weakness group (p=0.01). Vitamin D levels were significantly correlated with HGST levels (r:0.362, p=0.001). Vitamin D levels were found to be an independent predictor of weakness according to HGST in logistic regression analysis (OR: 0.453, 95% Cl:0.138-0.769, p=0.05).

Conclusions

Low vitamin D level is an independent risk factor for muscle weakness in men aged more than 50 years. Therefore, vitamin D levels should be screened and early replacement should be initiated for the sake of improvement of muscle strength in elderly subjects that vulnerable for frailty.

Combined antihypertensive treatment is better than mono-therapy in hypertensive patients

BACKGROUND

Hypertension (HT) is a chronic condition associated with serious complications. In the present cross-sectional study, we aimed to analyse factors that contribute to blood pressure control in subjects with HT.

METHODS

Subjects with HT admitted to outpatient internal medicine clinics of the institution were enrolled in the study. According to the Joint National Committee (JNC) VIII criteria, subjects with a mean blood pressure above target levels were defined as poorly-controlled hypertensive patients and others were grouped as well-controlled hypertensive patients. Clinical and laboratory parameters were compared between study groups.

RESULTS

Smokers were more prevalent in the poorly-controlled HT group compared to the well-controlled HT group (p = 0.001). The number of patients who adhered to dietary and exercise recommendations were greater in well-controlled HT group than poorly-controlled HT group (p < 0.001 for both). The rate of combined therapy was greater in well-controlled HT group compared to poorly-controlled HT group (p = 0.04).

CONCLUSIONS

We suggest that, in addition to dietary and exercise recommendations and smoking cessation, treatment with combination therapy could be better in reaching blood pressure targets in patients with HT.

Antiproliferative, antioxidant, computational and electrochemical studies of new azo-containing Schiff base ruthenium(ii) complexes

A new series of ruthenium(ii) complexes 7–11 containing the –NN– group are synthesized and characterized via elemental analysis, and IR, UV-visible and ¹H–¹³C NMR spectroscopy.

Effect of saliva decontamination procedures on shear bond strength of a one-step adhesive system

AIM

To evaluate the effect of different saliva decontamination procedures on the shear bond strength of a one-step universal adhesive system (Single Bond™ Universal Adhesive, 3M ESPE, St. Paul, MN, USA).

MATERIALS AND METHODS

The occlusal surfaces of 75 human third molars were ground to expose dentin. The teeth were divided into the following groups: Group 1 (control group): Single Bond™ Universal Adhesive was applied to the prepared tooth according to the manufacturer's recommendations and light cured; no contamination procedure was performed. Group 2: Bonding, light curing, saliva contamination, and dry. Group 3: Bonding, light curing, saliva contamination, rinse, and dry. Group 4: After the procedure performed in Group 2, reapplication of bonding. Group 5: After the procedure performed in Group 3, reapplication of bonding. Then, composite resins were applied with cylindrical-shaped plastic matrixes and light cured. For shear bond testing, a notch-shaped force transducer apparatus was applied to each specimen at the interface between the tooth and composite until failure occurred. The data were statistically analyzed using one-way ANOVA.

RESULTS

One-way ANOVA revealed significant differences in shear bond strength between the control group and experimental Groups 2 and 4 (P < 0.05). No significant difference was found for experimental Groups 3 and 5 when compared to the control group (P > 0.05).

CONCLUSION

The present in vitro study showed that water rinsing is necessary if cured adhesive resin is contaminated with saliva to ensure adequate bond strength.

Effect of nursing care given at home on the quality of life of patients with stomach cancer and their family caregivers' nursing care

In Turkey, the high incidences of stomach and oesophageal cancers in East and high incidence of stomach cancer in Northeast regions are remarkable. This study was conducted to identify homecare needs of patients with stomach cancer and their caregivers and the effect of family supportive nursing care on the quality of life of patients and families. The patient and his/her caregiver were assessed with respect to their daily life activities and NANDA was used for the identified nursing diagnoses, NIC for the appropriate interventions and NOC for assessment of the results. This study was conducted in a pre-test, post-test, controlled trial model to identify. The sample of the investigation consisted of 72 patients and 72 caregivers. As a data-collecting instrument, the Quality of Life Scale and Caregiver Quality of Life Index-Cancer were used. The overall quality of life, global health status and emotional and cognitive functions of the patients in the experimental group improved after the interventions. The overall quality of life and global health status was found to be poorer in the control group patients at post-test as compared to pre-test and their physical, role and social functions deteriorated. The caregivers' quality of life in the control group was affected more negatively with respect to the "Disruption in Daily Life" subscale as compared to pre-test values.

Chandelier retroillumination-assisted cataract surgery during vitrectomy

PurposeTo present an alternative cataract surgical technique in patients with cataract and intravitreal hemorrhage.MethodsTwelve cases with poor fundus reflex caused by severe vitreus hemorrhage were included in the study. All patients underwent combined phaco surgery and 23-gauge vitrectomy. Chandelier retroillumination was inserted into the infusion trochar during the cataract operations and was used with low power (50-75%) in necessary steps.ResultsWe did not experience phaco complications or complications due to technique during surgery. Retroillumination assistance was especially useful during final stages of cataract surgery, particularly irrigation-aspiration of cortical material.ConclusionRetroillumination in absence of red fundus reflex may be helpful and can be practiced more often in cataract surgery combined with vitrectomy.

Role of inflammation in sensory neuropathy in prediabetes or diabetes

OBJECTIVES

Prediabetes includes individuals with impaired glucose metabolism, and it has been associated with various complications of diabetes mellitus (DM), including peripheral neuropathy. We aimed to investigate the associations between pro-inflammatory (TNF-α) and anti-inflammatory (IL-10) cytokines and neuropathy of very distal sensory nerves in patients with prediabetes or type 2 DM.

MATERIALS AND METHODS

We included 50 patients with prediabetes, 50 patients with type 2 DM, and 44 controls in the study. Plasma levels of HbA1c, TNF-α, and IL-10 were analyzed. Electrodiagnostic testing was performed on dorsal sural and medial plantar sensory nerves, which are the very distal sensory nerves of the feet.

RESULTS

Abnormalities in nerve conduction studies (NCS) of the dorsal sural and medial plantar sensory nerves were substantially higher in patients with prediabetes or type 2 DM. In addition, plasma levels of TNF-α were significantly higher in patients with type 2 DM than in controls, whereas IL-10 levels were significantly lower in patients with both prediabetes and diabetes. However, we found no correlation between the levels of HbA1c, TNF-α, IL-10, and abnormalities in NCS of the dorsal sural or medial plantar sensory nerves in either patient group.

CONCLUSIONS

To our knowledge, this is the first study to assess the relationships between TNF-α, IL-10, and NCS of the most distal sensory nerves in patients with prediabetes or type 2 DM. The mechanisms involved in the pathogenesis of DM and diabetic peripheral neuropathy are complex. The pro-inflammatory stage and the high incidence of neuropathy in patients with prediabetes may suggest a possible causative effect; however, the potential role of inflammation in the pathogenesis of peripheral neuropathy needs further clarification.

Association between frontal sinus development and persistent metopic suture

BACKGROUND

Frontal sinuses are 2 irregular cavities, placed between 2 lamina of frontal bone. Expansion continues during childhood and reaches full size after puberty. Persistent metopic suture is one of the factors that are related to abnormal frontal sinus development. In this study, we want to discuss about the coexistence of persistent metopic suture and abnormal frontal sinus development using radiological techniques.

MATERIALS AND METHODS

In this retrospectively planned study, images of 631 patients were examined, 217 (34.4%) of them were men and 414 (65.6%) of them were women. Brain computed tomography and magnetic resonance images were retrieved from the electronic archive for analysis.

RESULTS

In this study, frontal sinus development is categorised as right side atrophy, left side atrophy, bilateral atrophy and bilaterally developed sinuses. The presence of metopic suture was accepted as persistent metopic suture. Frontal sinus atrophy was found in 22.7% and persistent metopic sutures were found in 9.7% of overall.

CONCLUSIONS

In this study, no significant results were detected that were relatedto the frontal sinus agenesis or dismorphism associated with persistent metopicsuture. We conclude that, although publications propounding metopism thatleads to abnormal frontal sinus development are present in the literature, noreasonable explanation has been mentioned in these articles; and we believe thatthese findings are all incidental.

Traumatic brain injury shows better functional recovery than brain tumor: a rehabilitative perspective

BACKGROUND

The similar symptoms seen in the brain tumor (BT) and traumatic brain injury (TBI) population. However, functional comparisons between these two diagnostic groups have been limited.

AIM

To compare functional outcomes in patients with supratentorial BT and TBI after early rehabilitation.

DESIGN

This was a retrospective database analysis. Setting. Patients admitted to an Acute Care Unit as inpatient (Hacettepe Hospital, Ankara-Turkey). Population. The population included patients with BT and TBI.

METHODS

Thirty-four patients with BT and TBI were matched one-to-one by lesion side and sex. The Barthel Index was used to assess functional status at the pre- and postrehabilitation. The change rate and efficiency in BI were also calculated. The time between injury onset and admission to rehabilitation (the onset to admission interval, OAI) and length of stay in rehabilitation (LOS rehab) were recorded. In addition, the influence of lesion side (left and right) and age on functional outcome were analyzed.

RESULTS

The functional level was significantly lower in TBI patients than in patients BT before rehabilitation (P<0.05). The post-rehabilitation BI score was similar in patients with BT and TBI (P>0.05). Patients with TBI had greater the change rate and efficiency in BI (P<0.05). The OAI and LOS rehab was longer in patients with TBI (P<0.05). In terms of lesion side comparisons, no differences were found (P>0.05). The age had no effect on functional outcome in patients with TBI and BT (P>0.05), expect the age group 45-59 (P<0.05).

CONCLUSION

The early rehabilitation program improved functional ability of patients with brain tumors, as well as patients with traumatic brain injury. Despite the lower functional status, patients with TBI displayed better functional recovery than patients with BT. Lesion side had no effect on functional outcome in patients with TBI and BT. Differences in functional status begin to appear even in patients with TBI between 45 and 59 years. Further investigations with more detailed outcome instruments are required to better understand the qualitative limitations of a patient's recovery.

CLINICAL REHABILITATION IMPACT

Patients with TBI will make functional gains comparable with patients with brain tumors in a similar rehabilitation setting.

Maternal deaths associated with H1N1 influenza virus infection in Turkey: a whole-of-population report

OBJECTIVE

To review the clinical and demographic characteristics of pregnant and postpartum women who died as a consequence of influenza A H1N1 (2009) infection in Turkey.

DESIGN

A review of the records for pregnant and postpartum women who died as a consequence of H1N1 influenza virus infection.

SETTING

Nationwide in Turkey.

POPULATION

Thirty-six pregnant or postpartum women who died as a result of confirmed pandemic H1N1 influenza virus infection.

METHODS

Using the General Directorate of Mother and Child Health and Family Planning (MCHFP) Registry of the Ministry of Health of Turkey, we identified all pregnant and postpartum women who died as a result of confirmed influenza A H1N1 (2009) infection between 29 October and 31 December 2009.

MAIN OUTCOME MEASURE

Maternal mortality as a result of H1N1 virus infection.

RESULTS

The average time from symptom onset to initial presentation for health care was approximately 2.5 days, and the mean time from symptom onset to the receipt of antiviral medication was approximately 5.5 days. Only one-fifth of all women received early antiviral treatment (administered 2 days or less after symptom onset) and only one woman was vaccinated for H1N1 influenza 1 week before the onset of symptoms. The cause-specific maternal mortality ratio for H1N1 influenza infection in Turkey was estimated to be 3.01. The calculated risk of death associated with H1N1 influenza virus infection was approximately four times higher in pregnant and postpartum women than in the general population (relative risk, 3.88; 95% confidence interval, 2.77-5.43).

CONCLUSIONS

Pregnant women are at increased risk for complications of, and death from, H1N1 influenza infection. Prompt evaluation and antiviral treatment of influenza-like illness should be considered in such women. Vaccination for H1N1 influenza may reduce the total number of deaths in pregnant and postpartum women. The high cause-specific maternal mortality rate suggests that H1N1 influenza virus infection may have increased the 2009 maternal mortality ratio in Turkey.

Subclinical anterior horn cell involvement in juvenile myoclonic epilepsy

Although clinical signs of muscle wasting and weakness were not present, electromyographic (EMG) evidence of subclinical anterior horn cell involvement of spinal cord was noted in 5 patients with juvenile myoclonic epilepsy (JME). Quantitative interference pattern analysis of EMG recorded from the anterior tibial muscle showed that the ratio (amplitude:turn/turn:second, A:T/T:S) was significantly increased in 10 patients with JME and 12 patients with lower motor neuron disorders (LMND) as compared with those of 22 normal subjects and 15 patients with frequent generalized tonic-clonic seizures (GTC). Subclinical anterior horn cell involvement detected by EMG techniques can be related to a genetically determined component of JME.

Calcium mobilization, prostaglandin E2 and alpha 2-adrenoceptor modulation of glucose utilization and insulin secretion in pancreatic islets

alpha 2-Adrenoceptor agonists inhibit glucose-stimulated insulin release and glucose utilization in pancreatic islets. In isolated pancreatic islets of the rat, the Ca2+ channel agonists CGP-28392 and BAY-K-8644 increased insulin release in the presence of clonidine. Neither CGP-28392 nor BAY-K-8644 antagonized the effect of clonidine on glucose utilization. The Ca2+ ionophore, ionomycin, also did not affect glucose utilization in the presence or absence of clonidine. Glucagon partly reversed the effects of clonidine on insulin release, and it potentiated glucose-stimulated insulin release in the absence of clonidine. Glucagon reversed the effects of clonidine on glucose utilization. Amiloride antagonized the effects of clonidine on insulin secretion but did not enhance markedly glucose utilization in the presence or absence of clonidine. Carbamylcholine and arecoline reversed the effects of clonidine on glucose utilization and partly reversed the effects on insulin release in the absence of extracellular Ca2+. Prostaglandin (PG) E2, but not PGF2 alpha, inhibited glucose utilization in a time- and concentration-dependent manner. PGE2 also inhibited glucose-stimulated insulin release. Pertussis toxin blocked both actions of PGE2. The cyclooxygenase inhibitor indomethacin did not affect insulin release or glucose utilization in the presence of clonidine. Thus, elevated intracellular Ca2+ levels antagonize the effects of clonidine on insulin release, whereas other mediators appear to be required to alter glucose utilization.

Alpha 2-adrenergic inhibition of pancreatic islet glucose utilization is mediated by an inhibitory guanine nucleotide regulatory protein

The rate of glucose utilization in isolated pancreatic islets of the rat was inhibited by the alpha 2-adrenoceptor agonists clonidine and epinephrine. Yohimbine reversed the inhibition. alpha 1 or beta-adrenoceptor agonists had little or no effect on glucose utilization. Stimulation of muscarinic receptors by carbamylcholine reversed the effect of clonidine. Pertussis toxin blocked the effect of clonidine on glucose utilization, and potentiated the response to carbamylcholine. 8-Bromo-cAMP did not affect glucose utilization in the presence of clonidine. Thus, alpha 2-adrenoceptors negatively modulate glucose utilization, and the effect is mediated by an inhibitory guanine nucleotide regulatory protein, but not by cAMP.

Pancreatic islet arachidonic acid turnover and metabolism and insulin release in response to delta-9-tetrahydrocannabinol

Isolated pancreatic islets from the rat secrete insulin in response to glucose or delta-9-tetrahydrocannabinol (THC). THC stimulated the basal release of insulin and also potentiated the secretory response to glucose. The exposure of control or glucose-stimulated islets to THC inhibited the incorporation of [14C]arachidonic acid (AA) into phospholipids. However, in islets prelabeled with [14C]AA, THC enhanced the glucose-induced loss of AA from phospholipids. The enhanced AA release from islet phospholipids in response to glucose and THC was accompanied by increased synthesis of 12-L-[5,6,8,9,11,12,14,15-3H(N)]-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) and prostaglandin E2. The lipoxygenase inhibitor 3-amino-1-(3-trifluoromethylphenyl)-2-pyrazoline hydrochloride (BW755C) inhibited 12-HETE synthesis and insulin release in glucose and THC-challenged islets; nordihydroguaiaretic acid also inhibited insulin release in THC-treated islets. In contrast, the cyclooxygenase inhibitor, indomethacin, stimulated insulin release. In homogenized islet preparations, THC inhibited acyl-CoA acyltransferase, while it stimulated phospholipase A2 activity. The stimulatory effects of THC on islet cell AA hydrolysis from phospholipids, lipoxygenase product formation, and secretion suggests that these biochemical sequelae in cell activation are important modulators of insulin release.