Oncologists' perceived confidence and attitudes toward managing pre-existing chronic comorbidities during patients' active cancer treatment

PURPOSE

To examine practicing oncologists' perceived confidence and attitudes toward management of pre-existing chronic conditions(PECC) during active cancer treatment(ACT).

METHODS

In December 2018, oncologists in the National Cancer Institute's Community Oncology Research Program (NCORP) were invited to complete a was pilot-tested, IRB-approved online survey about their perceived confidence in managing PECC. Pearson chi-square test was used to identify oncologists' differences in perceived confidence to manage PECC and attitudes toward co-management of patients' PECC with non-oncologic care providers. Perceived confidence and attitudes were analyzed as a function of medical specialty while controlling demographic and medical practice variables.

RESULTS

A total of 391 oncologists responded to the survey, 45.8% stated medical oncology as their primary specialty, 15.1% hematology oncology, 15.1% radiation oncology, 6.9% surgical oncology, and 17.1% other specialties such as gynecology oncology. Overall, 68.3% agreed (agree/strongly agree) that they were confident to manage PECC in the context of standard of care. However, only 46.6% and 19.7% remained confident when managing PECC previously managed by a primary care physician (PCP) and by a non-oncology subspecialist, respectively. Most oncologists (58.3%) agreed that patients' overall care was well coordinated, and 63.7% agreed that patients had optimal cancer and non-cancer care when PECC was co-managed with a non-oncology care provider.

CONCLUSION

Most oncologists felt confident to manage all PECC during patients' ACT, but their perceived confidence decreased for PECC previously managed by PCPs or by non-oncology subspecialists. Additionally, they had positive attitudes toward co-management of PECC with non-oncologic care providers. These results indicate opportunities for greater collaboration between oncologists and non-oncology care providers to ensure comprehensive and coordinated care for cancer patients with PECC.

Health Equity Among Black Women in the United States

Black women in the United States have experienced substantial improvements in health during the last century, yet health disparities persist. These health disparities are in large part a reflection of the inequalities experienced by Black women on a host of social and economic measures. In this paper, we examine the structural contributors to social and economic conditions that create the landscape for persistent health inequities among Black women. Demographic measures related to the health status and health (in)equity of Black women are reviewed. Current rates of specific physical and mental health outcomes are examined in more depth, including maternal mortality and chronic conditions associated with maternal morbidity. We conclude by highlighting the necessity of social and economic equity among Black women for health equity to be achieved.

U.S. Maternal Mortality Within a Global Context: Historical Trends, Current State, and Future Directions

In the United States, despite significant investment and the efforts of multiple maternal health stakeholders, maternal mortality (MM) has reemerged since 1987 and MM disparity has persisted since 1935. This article provides a review of the U.S. MM trajectory throughout its history up to its current state. From this longitudinal perspective, MM trends and themes are evaluated within a global context in an effort to understand the problems and contributing factors. This article describes domestic and worldwide strategies recommended by maternal health stakeholders to reduce MM.

Abstract D079: Oncologists’ approach in managing pre-existing chronic comorbidities during patients’ active cancer treatment

Background Cancer frequently occurs with other chronic diseases, and this poses serious care coordination challenges during patients’ active cancer treatment (ACT) and contributes to disparities in health outcomes. There is limited research addressing pre-existing chronic comorbidity (PCC) management during ACT. This study aimed to examine oncologists’ approach for PCC management during ACT. Methods Oncologists in the National Cancer Institute’s Community Oncology Research Program (NCORP) were surveyed about their approach in managing PCC. The Likert scale survey was piloted-tested, IRB-approved, and administered to oncologists. In December 2018, NCORP network oncologists were sent an email invitation to complete the online survey. Pearson chi-square test was used to identify differences in oncologists’ management approach of PCC. Results Among the 375 respondents of the ongoing survey, 45.6% practiced primarily as medical oncologists, 37.3% as hematology, surgical, or radiation oncologists, and 17.1% as other oncology specialists. Approximately 70% of oncologists reported that >50% of their patients had ≥ 1 PCC. When asked about the three most challenging PCC to manage, 23.3% cited diabetes, 19.5% cited heart disease, and 57.1% cited another PCC. Medical oncologists were more likely to cite diabetes first (77.5%) and less likely (22.5%) to cite heart disease first compared to other specialists (p=0.004). Co-management with patients’ PCP was the most common management approach for diabetes among medical oncologists (42.2%) compared to those of other specialties (15.0%) while referral to other physicians was the most common approach among those of other specialties (50.0%) compared to medical oncologists (22.5%) (p=0.002). Consultation and referral were the most common management approaches for heart disease across oncology specialties. Conclusion Oncologists face significant challenges to manage patients’ PCC during ACT. These results indicate that the medical oncologist is more likely to co-manage diabetes with patients’ PCP compared to other oncology specialists, but heart disease was seldom co-managed. Greater collaboration between oncology and non-oncology specialists is needed for effective management of PCC during ACT to ensure complete and coordinated care and to reduce disparities in health outcomes for these patients.

Citation Format: Dudith Pierre-Victor, Iman K. Martin, Brenda Adjei, Mary Shaw-Ridley, Bruce Rapkin, Marjorie Good, Diane ST. Germain, Bernard Parker, Worta McCaskill-Stevens. Oncologists’ approach in managing pre-existing chronic comorbidities during patients’ active cancer treatment [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D079.

Impact of comorbidity and age on treatment choice among men with localized prostate cancer

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Background: Prostate cancer (PCa) is the most commonly diagnosed cancer among men in the United States. A substantial proportion of PCa patients has at least one comorbidity. Comorbidities have a meaningful impact on cancer treatment choice. The objective of this study was to investigate the effect of comorbidity, as well as age, on treatment choice among men with localized PCa. Methods: From the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, men with localized PCa diagnosed from 1994-2014 were selected (N = 10, 281). Comorbidity score was determined based on a modified Charlson index. Treatment was classified as curative, either radical prostatectomy (RP) or radiation therapy with curative intent (RT), or non-curative (all other modalities). We used multivariate logistic regression to assess the association of treatment choice with age and comorbidity score (including their interaction), controlling for D’Amico risk group, demographics and diagnosis year. Results: About half (48.3%) of patients had comorbidity score ≥ 1. Most men received curative treatment (75.2%); RT (55.2%) was more common than RP (44.8%). The likelihood of curative treatment decreased with increasing age; odds ratios (OR) for curative treatment were 0.63 (95%CI: 0.52-0.76), 0.36 (95%CI: 0.30-0.43) and 0.13 (95%CI: 0.11-0.16) for men aged 65-69, 70-74 and 75+, respectively, compared to men aged 55-64. Men with a comorbidity score of 2+ (OR = 0.84; 95%CI: 0.74-0.96) were less likely to receive curative treatment than men with a score of 0. Within curative treatment, older age was strongly associated with RT. Compared to men aged 55-64 years, men aged 65-69 years (OR = 2.0; 95% CI: 1.72-2.3), 70-74 years (OR = 5.3; 95% CI: 4.5-6.3), and 75+ years (OR = 25.0; 95% CI: 17-33) were more likely to receive RT than RP. Men with a comorbidity score of 1 (OR = 1.16; 95%CI: 1.03-1.30) or 2+ (OR = 1.92; 95%CI: 1.6-2.3) were also more likely to receive RT. The interaction between age and comorbidity score was not significant. Conclusions: In this cohort, age was a strong independent predictor of treatment choice for localized PCa. Although comorbidity was not a strong predictor of curative treatment, it was associated with receipt of RT.

Oncologists’ perceived confidence in managing pre-existing chronic comorbidities during patients’ active cancer treatment

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Background: Cancer frequently occurs with other chronic diseases, and this poses serious care coordination challenges during patients’ active cancer treatment (ACT). There is limited research addressing chronic comorbidity (CC) management during ACT. This study aimed to examine practicing oncologists’ perceived confidence in independently managing CC during ACT. Methods: Oncologists in the National Cancer Institute’s Community Oncology Research Program (NCORP) were surveyed about their perceived confidence in managing CC. The Likert scale survey was piloted-tested, IRB-approved, and administered to oncologists. In December 2018, NCORP network oncologists were sent an email invitation to complete the online survey. Pearson chi-square test was used to identify oncologists’ differences in perceived confidence in managing CC. Results: Among the 201 respondents of the ongoing survey, 48% were medical oncologists, 21.2% radiation or surgical oncologists, and 30.8% were of other specialties. Overall, 69% agreed (agree or strongly agree), 17.3% were neutral, and 13.4% disagreed (strongly disagree or disagree) that they were confident in managing all CC independently. While 69% of oncologists were confident when managing any CC, only 49% and 19.8% remained confident when managing CC previously managed by a primary care physician (PCP) and by a non-oncology subspecialist, respectively. Across oncologic subspecialties, 47.6%, 77.9% and 72.1% of radiation/surgical oncologists, medical oncologists, and those of other specialties, respectively, agreed that they were confident in independently managing CC (p = 0.003). Conclusions: Most oncologists are confident in managing all CC during patients’ ACT. However, they were less confident with CC previously managed by PCPs, and even less confident for CC previously managed by non-oncology subspecialists. These results indicate opportunities for greater collaboration between oncology and non-oncology specialists to ensure complete and coordinated care for cancer patients with comorbidities.

Self-reported Black race predicts significant prostate cancer independent of clinical setting and clinical and socioeconomic risk factors

INTRODUCTION AND OBJECTIVE

Studies have linked Black race to prostate cancer (CaP) risk but most fail to account for established risk factors such as 5-ARI use, prostate volume, socioeconomic status, and hospital setting. We assess whether Black race remains associated with CaP and Gleason ≥3 + 4 CaP, after adjusting for clinical setting and socioeconomic and clinical factors at prostate biopsy, with a focus on men aged 40-54 years, who may be excluded from current screening guidelines.

METHODS

We recruited 564 men age 40-79 undergoing initial prostate biopsy for abnormal PSA or digital rectal examination (DRE) from three publicly funded and two private hospitals from 2009-2014. Univariate and multivariate analyses examined the associations between hospital type, race, West African Ancestry (WAA), clinical, and sociodemographic risk factors with CaP diagnosis and Gleason ≥3 + 4 CaP. Given changes in CaP screening recommendations, we also assess the multivariate analyses for men aged 40-54.

RESULTS

Black and White men had similar age, BMI, and prostate volume. Black men had higher PSA (8.10 ng/mL vs. 5.63 ng/mL) and PSA density (0.22 ng/mL/cm³ vs. 0.15 ng/mL/cm³, all p < 0.001). Blacks had higher frequency of CaP (63.1% vs. 41.5%, p<0.001) and Gleason ≥3+4 CaP relative to Whites in both public (27.7% vs 11.6%, p<0.001) and private (48.4% vs 21.6%, p = 0.002) settings. In models adjusted for age, first degree family history, prostate volume, 5-ARI use, hospital type, income, marital and educational status, Black race was independently associated with overall CaP diagnosis (OR = 2.13, p = 0.002). There was a significant multiplicative interaction with Black race and abnormal DRE for Gleason ≥3 + 4 CaP (OR = 2.93, p = 0.01). WAA was not predictive of overall or significant CaP among Black men. Black race (OR = 5.66, p = 0.02) and family history (OR = 4.98, p = 0.01) were independently positively associated with overall CaP diagnosis for men aged 40 to 54.

CONCLUSIONS

Black race is independently associated with CaP and Gleason ≥3+4 CaP after accounting for clinical and socioeconomic risk factors including clinical setting and WAA, and has a higher odds ratio of CaP diagnosis in younger men. Further investigation into optimizing screening in Black men aged 40 to 54 is warranted.

Abstract B034: Time to treatment and overall survival among men with localized prostate cancer

Background: Prostate cancer is the second most common cancer diagnosed among men in the United States. Delays from the time of confirmed diagnosis to primary treatment are more common for prostate compared to other malignancies. The objective of this study was to investigate factors associated with time to treatment and the effect of time to treatment on overall survival among men with early-stage prostate cancer.

Methods: From the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, men diagnosed with localized prostate cancer who received treatment within a year of diagnosis were selected for analysis (N=6,349). Selected men had date of diagnosis, treatment date, and mortality status as of 2012. We investigated sociodemographic and clinical factors associated with time to treatment using Cox regression. We also used Cox regression to examine the effect of time to treatment on overall survival. Covariates included Gleason score, PSA level, age at diagnosis, employment status, education level, race, marital status, and comorbidity burden.

Results: The median time to treatment was 73 (IQR: 44-120) days. Demographic factors associated with longer time to treatment included being Black (adjusted hazard ratio (aHR)= 0.85, 95%CI: 0.76-0.95), having some college education (aHR= 0.91, 95%CI: 0.85-0.97), and having a baccalaureate degree or a post-baccalaureate degree (aHR= 0.89, 95% CI: 0.84-0.95). Clinical factors associated with longer time to treatment were being diagnosed at an older age (aHR= 0.86, 95%CI:0.80-0.93 for age of 70-74 years and aHR= 0.80, 95%CI: 0.74-0.87 for 75 year and older) and having an elevated PSA level (HR=0.89, 95%CI: 0.81-0.94 for third PSA quartile (6.11-9.0) and HR=0.87, 95%CI: 0.81-0.94 for fourth PSA quartile (9.0 and above). Gleason score and comorbidity burden were not associated with time to treatment. Being married (aHR=1.11, 95%CI: 1.03-1.19) and being retired (aHR=1.09, 95%CI:1.034-1.16) were associated with shorter time to treatment. After adjusting for sociodemographic and clinical characteristics, time to treatment did not have a significant effect on overall survival.

Conclusions: College education, being Black, older age at diagnosis, and higher PSA levels were associated with longer time to treatment. Being married and being retired were associated with shorter time to treatment. Longer time to treatment was not associated with overall mortality among PLCO men with localized prostate cancer.

Citation Format: Dudith Pierre-Victor, Paul Pinsky, Iman K. Martin, Worta McCaskill-Stevens. Time to treatment and overall survival among men with localized prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B034.

Vitamin D deficiency predicts prostate biopsy outcomes

PURPOSE

The association between vitamin D and prostate biopsy outcomes has not been evaluated. We examine serum vitamin D levels with prostate biopsy results in men with an abnormal prostate-specific antigen and/or digital rectal examination.

EXPERIMENTAL DESIGN

Serum 25-hydroxyvitamin D (25-OH D) was obtained from 667 men, ages 40 to 79 years, prospectively enrolled from Chicago urology clinics undergoing first prostate biopsy. Logistic regression was used to evaluate the associations between 25-OH D status and incident prostate cancer, Gleason score, and tumor stage.

RESULTS

Among European American (EA) men, there was an association of 25-OH D <12 ng/mL with higher Gleason score ≥ 4+4 [OR, 3.66; 95% confidence interval (CI), 1.41-9.50; P = 0.008] and tumor stage [stage ≥ cT2b vs. ≤ cT2a, OR, 2.42 (1.14-5.10); P = 0.008]. In African American (AA) men, we find increased odds of prostate cancer diagnosis on biopsy with 25-OH D < 20 ng/mL [OR, 2.43 (1.20-4.94); P = 0.01]. AA men demonstrated an association between 25-OH D < 12 ng/mL and Gleason ≥ 4+4 [OR, 4.89 (1.59-15.07); P = 0.006]. There was an association with tumor stage ≥ cT2b vs. ≤ cT2a [OR, 4.22 (1.52-11.74); P = 0.003].

CONCLUSIONS

In AA men, vitamin D deficiency was associated with increased odds of prostate cancer diagnosis on biopsy. In both EA and AA men, severe deficiency was positively associated with higher Gleason grade and tumor stage.

Are HIV-infected men vulnerable to prostate cancer treatment disparities?

BACKGROUND

HIV-infected (HIV(+)) men face cancer treatment disparities that impact outcome. Prostate cancer treatment and treatment appropriateness in HIV(+) men are unknown.

METHODS

We used electronic chart review to conduct a retrospective cohort study of 43 HIV(+) cases with prostate cancer and 86 age- and race-matched HIV-uninfected (HIV(-)) controls with prostate cancer, ages 40 to 79 years, from 2001 to 2012. We defined treatment appropriateness using National Comprehensive Cancer Network guidelines and the Charlson comorbidity index (CCI) to estimate life expectancy.

RESULTS

Median age was 59.5 years at prostate cancer diagnosis. Median CD4(+) T-cell count was 459.5 cells/mm(3), 95.3% received antiretroviral therapy, and 87.1% were virally suppressed. Radical prostatectomy was the primary treatment for 39.5% of HIV(+) and 71.0% of HIV(-) men (P = 0.004). Only 16.3% of HIV(+) versus 57.0% of HIV(-) men received open radical prostatectomy (P < 0.001). HIV(+) men received more radiotherapy (25.6% vs. 16.3%, P = 0.13). HIV was negatively associated with open radical prostatectomy (OR = 0.03, P = 0.007), adjusting for insurance and CCI. No men were undertreated. Fewer HIV(+) men received appropriate treatment (89.2% vs. 100%, P = 0.003), due to four overtreated HIV(+) men. Excluding AIDS from the CCI still resulted in fewer HIV(+) men receiving appropriate treatment (94.6% vs. 100%, P = 0.03).

CONCLUSION

Prostate cancer in HIV(+) men is largely appropriately treated. Under- or overtreatment may occur from difficulties in life expectancy estimation. HIV(+) men may receive more radiotherapy and fewer radical prostatectomies, specifically open radical prostatectomies.

IMPACT

Research on HIV/AIDS survival indices and etiologies and outcomes of this prostate cancer treatment disparity in HIV(+) men are needed.

Smoking and prostate cancer in a multi-ethnic cohort

BACKGROUND

Prostate cancer (PCa) and smoking-related morbidity disproportionately burdens African American (AA) men. Smoking is associated with high-grade PCa and incidence, but few studies have focused on AA men. This study aims to determine the effect of tobacco-use on odds of PCa and of high-grade PCa in a population of predominantly AA men.

METHODS

This is a cross-sectional study evaluating smoking and PCa status in men with incident PCa and screened healthy controls. Altogether, 1,085 men (527 cases and 558 controls), age ≥ 40 years were enrolled through outpatient urology clinics in two US cities from 2001 to 2012. Validated questionnaires were used to gather clinical and socioeconomic data.

RESULTS

The cases and controls were predominantly AA (79.9% and 71.3%, respectively, P = 0.01). AA men smoked more frequently (53.4% vs. 47.9%, P < 0.001) and quit less frequently than European American (EA) men (31.5% vs. 40.4%, P = 0.01). AA heavy smokers had increased odds of PCa diagnosis (OR 2.57, 95% CI 1.09, 6.10) and high-grade cancer (OR 1.89, 95% CI 1.03, 3.48) relative to never smokers and light smokers. Among AAs, heavy smokers had lower odds of NCCN low PCa recurrence risk stratification. AA former smokers had a trend for increased odds of high-grade cancer compared to never smokers. The associations between smokings, cancer diagnosis and cancer grade did not reach statistical significance in EA men.

CONCLUSION

We found ethnic differences in smoking behavior. Heavy smoking is associated with increased odds of PCa and of higher Gleason grade in AA men.

Abstract 3598: The role of adiposity in racial and ethnic disparities in prostate cancer occurrence and progression: A systematic literature review

Background and Objective: Black men develop and die from prostate cancer (PCa) more than any other racial group. According to recent United States (US) statistics, PCa incidence and mortality rates in Black men are 1.6 and 2.4 times that of their White (WH) counterparts, respectively. Various biologic, behavioral, environmental, demographic, and social-contextual factors have been shown to be components of the persisting disparities in outcomes. However, it is not clear how aspects of body composition, particularly adiposity, contribute to racial and ethnic disparities in PCa occurrence and course. Current reviews on the adiposity relationship have tended not to adequately address this. Therefore, we conducted a systematic review of the literature examining the role of adiposity in racial disparities in prostate cancer. Methods: The US National Library of Medicine National Institutes of Health PubMed database was searched for English articles published through October 1, 2011. Criteria for selection were: 1) an adiposity-related factor (BMI, WHR etc.) was an exposure of interest and related to a PCa outcome (diagnosis, progression, prostate cancer-specific mortality); 2) focused on racial disparities in an adiposity association with PCa; 3) the participant sample included men of predominant African Ancestry [AA] (e.g. Black, African American, Ghanaian etc.); 4) and race-stratified, particularly AA specific, effect estimates for PCa occurrence, mortality, or progression were reported. Adjustment for race in a multivariate model alone was not sufficient for inclusion in the review analysis. No reviews, editorials, or comments were included in the review, although they were cited for background content. Results: Many of the available reviews on adiposity and PCa racial disparities focused on disparities in screening, rather than incidence, progression, or mortality. The articles which did address occurrence and outcomes often did not present race-specific effect estimates and simply adjusted for race in multivariate models. The available evidence suggests a unique role of adiposity-related factors (i.e. body size, body fat distribution, and fatty acid intake,) in the risk of PCa occurrence, progression, differences in treatment efficacy, and PCa-specific death. Lack of studies including sufficiently large numbers of AA prohibited reporting of race-specific estimates in many studies, especially in studies involving molecular biology and genetics. Conclusions: Incidence, morbidity, and mortality are highest in Black men. Clarifying the role of adiposity in PCa disparities is of great importance. Further clinical research illuminating adiposity related targets for intervention and mechanisms is crucial in this highly affected group.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3598. doi:1538-7445.AM2012-3598

Predictors of serum vitamin D levels in African American and European American men in Chicago

Vitamin D deficiency is epidemiologically linked to prostate, breast, and colon cancer. When compared with European American (EA) men, African American (AA) men have increased risk of prostate cancer, but few studies evaluate vitamin D status in AA men. The authors evaluate the biological and environmental predictors of vitamin D deficiency in AA and EA men in Chicago, Illinois, a low ultraviolet radiation environment. Blood samples were collected from 492 men, aged between 40 and 79 years, from urology clinics at three hospitals in Chicago, along with demographic and medical information, body mass index, and skin melanin content using a portable narrow-band reflectometer. Vitamin D intake and ultraviolet radiation exposure were assessed using validated questionnaires. The results demonstrated that Black race, cold season of blood draw, elevated body mass index, and lack of vitamin D supplementation increase the risk of vitamin D deficiency. Supplementation is a high-impact, modifiable risk factor. Race and sunlight exposure should be taken into account for recommended daily allowances for vitamin D intake.

Weight loss and African-American women: a systematic review of the behavioural weight loss intervention literature

The excess burden of obesity among African-American women is well documented. However, the behavioural weight loss intervention literature often does not report results by ethnic group or gender. The purpose of this article is to conduct a systematic review of all behavioural weight loss intervention trials published between 1990 and 2010 that included and reported results separately for African-American women. The criteria for inclusion included (i) participants age ≥18 years; (ii) a behavioural weight loss intervention; (iii) weight as an outcome variable; (iv) inclusion of African-American women; and (v) weight loss results reported separately by ethnicity and gender. The literature search identified 25 studies that met inclusion criteria. Our findings suggest that more intensive randomized behavioural weight loss trials with medically at-risk populations yield better results. Well-designed and more intensive multi-site trials with medically at-risk populations currently offer the most promising results for African-American women. Still, African-American women lose less weight than other subgroups in behavioural weight loss interventions. It is now critical to expand on individual-level approaches and incorporate the biological, social and environmental factors that influence obesity. This will help enable the adoption of healthier behaviours for this group of women disproportionately affected by obesity.

Abstract 1864: Differential effects of the isoflavone genistein on androgen receptor expression and cell proliferation comparing prostate cancer cells with mutant and wild type androgen receptor

In advanced prostate cancer, cells become androgen independent and therefore resistant to androgen ablation therapy. One mechanism by which prostate cancer bypasses androgen ablation therapy is acquisition of androgen receptor (AR) mutations some of which render it promiscuous enabling activation by a broad group of steroids such as estrogen, progesterone, and even anti-androgens. Genistein, an exogenous steroid (phytoestrogen) and isoflavone found in soy, has estrogenic activity. Most studies have shown that genistein has anti-proliferative effects on prostate cancer cells without regard for the status of the AR. It has been suggested that activation of the mutant AR (MT-AR) by genistein could lead to increased cellular proliferation. Previous studies examining genistein's effect on AR expression used prostate cell lines (i.e. LNCaP) with ARs carrying the promiscuous T877A mutation, without comparison to cells with wild type (WT) AR. Genistein does not bind WT-AR, and thus, may not have the same effect on AR expression as it does in the presence of MT-AR. We set out to compare the effects of genistein in the presence of WT-AR versus MT-AR, using human prostate cancer cell lines with WT-AR (LAPC-4) and MT-AR (LNCaP). Cells were treated with increasing concentrations (0, 0.5, 1, 10, 25, and 50 μM) of genistein. Real time PCR, Western blot analysis, PSA luciferase assay, cell counting by hemocytometer, and MTS proliferation assays were used to determine levels of AR mRNA, protein, transcriptional activity, and cell proliferation, respectively. Genistein caused an androgen-independent biphasic changes in AR mRNA, protein levels, and transcriptional activity, and in cell proliferation in LNCaP cells, which reached a maximum at 1μM of genistein (40-45% increase in AR protein and mRNA expression, 42% increase in PSA luciferase activity, and 2-fold increase in cell proliferation compared to controls). These effects reversed at a concentration of 10 μM. In contrast, in LAPC-4 cells AR mRNA and protein levels and transcriptional activity as well as cell proliferation decreased linearly with increasing dose of genistein, without showing the stimulatory bi-phasic trend observed in LNCaP cells. These decreases were significant, beginning at 1 μM genistein, at which concentration AR mRNA was reduced by 30%, protein expression by 22%, PSA luciferase activity by 40%, and cell proliferation by 56%. These results demonstrate that at physiological concentrations, genistein can exert a mitogenic effect in the presence of MT-AR. Our findings highlight the significance of promiscuous mutations such as T877A for the AR response to genistein treatment and indicate that men with advanced prostatic cancers which carry such AR mutations could be adversely affected by genistein. (Supported in part by Grant No. CA116195)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1864. doi:10.1158/1538-7445.AM2011-1864

Implementation of a percutaneous core needle biopsy training program: results from the University of Michigan-Komfo Anokye Teaching Hospital breast cancer research partnership

PURPOSE

To describe a training program in percutaneous core needle biopsy implemented in conjunction with a breast cancer research collaboration between the University of Michigan (UM) and the Komfo Anokye Teaching Hospital (KATH), Kumasi, Ghana.

METHODS

In July 2007 a Ghana-based training program for performance of core needle biopsy was jointly coordinated by the UM and KATH principal investigators (L.N. and B.A.). This course required less than 1 week for implementation.

RESULTS

Following the training course (July 2007 through August 2008), 82 core needle biopsies of breast masses were performed at KATH. Of these, 56 had tissue specimens available for review at UM for comparison with KATH primary pathology reports. Forty-six of the 56 UM-reviewed cases (82%) had a KATH diagnosis of breast cancer; UM pathology review was in agreement with the cancer diagnosis in all 46 cases (100%). Ten of the 56 UM-reviewed cases (18%) had a KATH diagnosis of benign fibroadenoma/fibrocystic breast tissue; UM review was concordant in all ten cases (100% concordance for benign lesions). For the remaining 26 procedures we were unable to retrieve either the KATH pathology report or tissue blocks for UM review.

DISCUSSION

The design and implementation of appropriate diagnostic biopsy programs is important for delivery of high-quality, efficient breast cancer care in developing nations. This study demonstrates a successful 1-week training program in percutaneous core needle biopsy for a multidisciplinary group of physicians. Further work is needed for similar programs to accurately identify and classify breast cancer internationally.

Descriptive epidemiology of selected olfactory tumors

Olfactory tumors, especially olfactory neuroblastomas (ON) and carcinomas with neuroendocrine differentiation (CND), are extremely rare, and little descriptive epidemiologic information is available. The objective of this study was to more fully describe selected olfactory tumors using a large population-based cancer incidence database. The Surveillance, Epidemiology and End Results (SEER) 9 registries limited-use data were reviewed from 1973 to 2006 for selected nasal cavity (C30.0) and accessory sinus (C31.0-31.9) tumors. Frequencies, incidence rates, and relative survival rates were estimated using SEER*Stat, v6.5.2. The majority of cases were squamous cell carcinoma (SCC), while the incidence of ON was greater than CND. For ON, the incidence was highest in the 60-79 year age group, while for SCC, the incidence was highest in the 80+ year age group. For CND, the incidence leveled off in the oldest age groups. Survival rates were highest for ON (>70% alive at 5 years after diagnosis) and poorest for CND (44% alive at 5 years). Adjuvant radiation therapy did not improve survival over surgery alone in ON. In SCC, survival was worse in patients who received adjuvant radiation compared to patients who had surgery alone. Our analysis confirms some previously published information, and adds new information about the incidence and demographics of ON and CND. In addition, our analysis documents the lack of benefit of adjuvant radiation in ON. It is not feasible to conduct prospective trials in patients with these rare diseases, and the importance of registry data in learning about olfactory tumors is emphasized.

3-p-Toluoyl-2-[4'-(3-diethylaminopropoxy)-phenyl]-benzofuran and 2-[4'-(3-diethylaminopropoxy)-phenyl]-benzofuran do not act as surfactants or micelles when inhibiting the aggregation of beta-amyloid peptide

The cmc and IC50 values of the beta-amyloid (Abeta) aggregation inhibitors, 3-p-toluoyl-2-[4'-(3-diethylaminopropoxy)-phenyl]-benzofuran 1, and 2-[4'-(3-diethylaminopropoxy)-phenyl]-benzofuran 2 have been determined. After comparison of the cmc data and biological data (IC50 values), we conclude that these active benzofurans do not act as surfactants or micelles at the concentration required to inhibit beta-amyloid-peptide aggregation.

Muscle glycogen storage following prolonged exercise: effect of timing of ingestion of high glycemic index food

This study examined the effect of delaying the ingestion of carbohydrate on muscle glycogen storage following prolonged exhaustive exercise. Six endurance trained men cycled on two separate occasions at a workload corresponding to 70% VO2max for 2 h followed by four "all-out" 30-s sprints. Following exercise, subjects were fed five high glycemic index (HGI) meals over a 24-h period, with the first three being fed either at 0-4 h (IT) or 2-6 h (DT) at 2-h intervals. Muscle biopsies were taken immediately after exercise and at 8 and 24 h post-exercise and analyzed for glycogen and glucose-6-phosphate. Blood samples were obtained prior to and at 30, 60, and 90 min after each meal and analyzed for glucose and insulin. No differences were observed in the incremental glucose and insulin areas after each meal when IT and DT were compared. In addition, no differences were observed in muscle glycogen or glucose-6-phosphate any time in the two trials. These data indicate that delayed feeding of a HGI meal by 2 h has no effect on the rate of muscle glycogen resynthesis at 8 and 24 h post-exercise, providing that sufficient carbohydrate is ingested during the recovery period.

Splanchnic and muscle metabolism during exercise in NIDDM patients

To characterize splanchnic and muscle metabolism during exercise in non-insulin-dependent diabetes mellitus (NIDDM), eight male nonobese patients and seven healthy control subjects (CON) were studied during 40 min of bicycle exercise at 60% of maximal oxygen uptake. Biopsies were obtained from the quadriceps femoris muscle at rest and immediately after exercise. Arterial glucose concentration in NIDDM had declined by 10% (P < 0.01) at the end of exercise, whereas in CON it had risen by 21% (P < 0.05). Leg glucose uptake rose from 0.19 +/- 0.06 mmol/min at rest to 2.25 +/- 0.61 mmol/min at the end of exercise in NIDDM and from 0.13 +/- 0.05 to 1.17 +/- 0.34 mmol/min in CON. Splanchnic glucose output increased from 0.52 +/- 0.06 to 2.37 +/- 0.26 mmol/min in NIDDM and from 0.79 +/- 0.12 to 2.44 +/- 0.38 mmol/min in CON. Leg lactate output during exercise was twofold higher in NIDDM. Muscle contents of lactate and glycogen were similar in both groups at rest, whereas after exercise lactate tended to be higher (19.5 +/- 1.7 vs. 12.7 +/- 5.9 mmol/kg dry wt) and glycogen lower (154 +/- 35 vs. 251 +/- 41 mmol glucosyl units/kg dry wt) in NIDDM. Whole body respiratory exchange ratio during exercise was higher in NIDDM (0.84 +/- 0.02 vs. 0.78 +/- 0.02, P < 0.05). Exercise-induced changes in other muscle metabolites were similar in NIDDM and CON. These data indicate that the decline in blood glucose during exercise in nonobese NIDDM is due to enhanced peripheral glucose utilization rather than to an attenuated increase in splanchnic glucose output.

Development of decreased insulin-induced glucose transport in skeletal muscle of glucose-intolerant hybrids of diabetic GK rats

1. The effect of glucose intolerance on insulin-stimulated glucose transport in isolated skeletal muscles was investigated in male F1 hybrids of spontaneously diabetic GK (Goto-Kakizaki) and control Wistar rats at 1 and 2 months of age. 2. Hybrid rats are characterized by markedly impaired glucose-induced insulin secretion. The area under the blood glucose curve was significantly higher following an intraperitoneal glucose injection (2 g/kg) in hybrid rats in both age groups than in the control rats (P < 0.001). In 2-month-old hybrid rats the incremental area under the insulin curve during the intraperitoneal glucose tolerance test was not different from that of control rats. Serum cholesterol, triacylglycerol or plasma free fatty acid levels did not differ between the groups. Fasting and post-prandial plasma glucose concentrations were elevated in 2-month-old hybrid rats compared with control rats (54%, P < 0.05, and 27%, P < 0.05, respectively), but were not different in 1-month-old rats. Plasma insulin did not differ between the hybrid and control rats in the fasting or post-prandial state at either age studied. 3. The insulin dose-response curves for 3-O-methylglucose transport did not differ between 1-month-old hybrid and control rats for either the soleus or epitrochlearis muscle. The insulin dose-response curve for the epitrochlearis, but not for the soleus, muscle from 2-month-old hybrid rats was shifted to the right compared with the curve from the control animals (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated free fatty acid levels inhibit glucose phosphorylation in slow-twitch rat skeletal muscle

The effect of increased free fatty acid concentrations on glucose metabolism in rat skeletal muscle was investigated at several different steps in glucose metabolism including glucose transport, glucose phosphorylation, glucose oxidation and glycogen synthesis. In isolated soleus (slow-twitch) muscles, insulin-stimulated (100 microU ml-1) glucose phosphorylation, but not glucose transport, was inhibited by 26 and 22% in the presence of 1.0 and 2.0 mM oleate, respectively (P < 0.01). Regardless of oleate concentration (0.3 or 2.0 mM), insulin-stimulated glucose 6-phosphate levels were elevated to the same extent over the non-insulin-stimulated levels in soleus muscles (P < 0.01). Insulin-stimulated glucose oxidation was inhibited by 44% in soleus muscles exposed to 2.0 mM oleate (P < 0.05), whereas the rate of glucose incorporation into glycogen was not altered. In insulin-stimulated epitrochlearis (fast-twitch) muscles, elevated concentrations of oleate had no effect on the rates of glucose transport or glucose phosphorylation, or on the level of glucose 6-phosphate. These data suggest that increased free fatty acid availability decreases glucose utilization by selectively inhibiting glucose phosphorylation and oxidation in slow-twitch, but not fast-twitch skeletal muscle.

Muscle metabolism during exercise and heat stress in trained men: effect of acclimation

Exercise metabolism was examined in 13 endurance athletes who exercised on three occasions for 40 min at 70% of maximal O2 uptake in an environmental chamber at either 20 degrees C and 20% relative humidity (RTT) or 40 degrees C and 20% relative humidity before (PRE ACC) or after (POST ACC) 7 days of acclimation. Exercise in the heat resulted in a lower (P < 0.05) mean O2 uptake (0.13 l/min) and higher (P < 0.01) heart rate and respiratory exchange ratio. Acclimation resulted in a lower (P < 0.01) mean heart rate and respiratory exchange ratio. Postexercise rectal temperature, muscle temperature, muscle and blood lactate, and blood glucose were higher (P < 0.01) in the PRE ACC than in the RTT trial, but all were reduced (P < 0.01) in the POST ACC compared with the PRE ACC trial. Muscle glycogenolysis and percentage of type I muscle fibers showing glycogen depletion were greater (P < 0.05) in the PRE ACC than in the RTT trial. Muscle glycogenolysis was unaffected by acclimation during exercise in the heat, although the percentage of depleted type I fibers was higher (P < 0.05) in the unacclimated state. Plasma epinephrine was higher (P < 0.01) during exercise in the heat in the unacclimated individual relative to RTT but was lower (P < 0.01) in the POST ACC than in the PRE ACC trial. The greater reliance on carbohydrate as a fuel source during exercise in the heat appears to be partially reduced after acclimation. These alterations are consistent with the observed changes in plasma epinephrine concentrations.

Effects of acute and chronic counterregulatory hormone infusions on glucose tolerance and insulin sensitivity in diabetic dogs

The effects of elevated EPI and CORT levels on KG, SI, and SG were studied in dogs with alloxan-induced diabetes. Conscious dogs received SAL, EPI 20 ng.kg-1.min-1 for 30 min (short EPI) or 72 h (long EPI), or CORT 200 micrograms.kg-1.min-1 for 60 min (short CORT) or 72 h (long CORT) before assessment of glucose metabolism by rapid sampling for glucose and insulin levels after 300 mg/kg i.v. glucose and exogenous insulin infusion designed to simulate the normal secretory pattern. With EPI infusion, KG fell acutely from 2.9 +/- 0.4 to 2.0 +/- 0.2%/min (SAL vs. short EPI, P < 0.05), but rose to 3.4 +/- 0.4%/min during long EPI. Minimal-model analysis of the glucose response with the insulin data as input showed that SI decreased acutely from 4.7 +/- 1.8 to 2.5 +/- 0.6 x 10(-5) min-1/pM (SAL vs. short EPI, P < 0.05), but rose to 4.5 +/- 2.5 x 10(-5) min-1/pM during long EPI. The effects of EPI on SG paralleled the results for KG and SI, with acute decline from 3.9 +/- 0.4 to 2.1 +/- 0.4 x 10(-2) min-1 (SAL vs. short EPI, P < 0.05) and recovery to 3.3 +/- 0.3 x 10(-2) min-1 during long EPI. During CORT infusion, KG tended to fall (SAL 2.9 +/- 0.4 vs. short CORT 2.5 +/- 0.5 vs. long CORT 2.2 +/- 0.5%/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Distinct but nonadditive effects of epinephrine and cortisol on determinants of glucose tolerance in dogs

Effects of physiological increments of epinephrine (Epi) and cortisol (F) on glucose metabolism were assessed in dogs just before and during an intravenous glucose tolerance test performed in the last 3 h of an acute (short F + Epi, 4 h F and 3.5 h Epi) or prolonged (long F + Epi, 75 h F and Epi) infusion period. Comparison of the F + Epi effects with those of F and Epi alone enabled us to describe interactions between these hormones. The increase in plasma glucose after long F + Epi [from control (saline, Sal) of 5.2 +/- 0.1 to 5.8 +/- 0.1 mmol/l; n = 8; P less than 0.01] was not greater than the sum of the glucose increments after long F and long Epi individually. Long Epi and long F both reduced glucose tolerance (KGlc) significantly, but the decline during long F + Epi (from Sal 3.6 +/- 0.7 to 2.9 +/- 0.5%/min; P greater than 0.1) was less than during either individual infusion. Minimal model analysis showed that F attenuated the inhibitory effects of long Epi on glucose-mediated glucose disposal (SGlc), so that it was not reduced from 3.8 +/- 0.8 (Sal) during long F + Epi compared with the fall to 1.3 +/- 0.7 x 10(-2) min-1 (n = 6; P less than 0.05) during long Epi alone. F had the dominant influence on insulin sensitivity (SI) during infusion of F + Epi. The reduction of SI from 8.4 +/- 1.1 (Sal) to 6.6 +/- 1.2 (short F + Epi) and 5.1 +/- 1.1 x 10(-4) min-1 per mU/l (long F + Epi; P less than 0.05) paralleled that seen with F alone but contrasted with the acute reduction of SI during short Epi (4.8 +/- 1.5; P less than 0.02 vs. Sal) and its restoration to control values of 9.0 +/- 2.1 x 10(-4) min-1 per mU/l during long Epi. We conclude that Epi and F have distinct but nonadditive effects on determinants of glucose tolerance.

Alternative method for minimal model analysis of intravenous glucose tolerance data

The minimal models of glucose-insulin kinetics were used to analyze sets of data obtained from human subjects and dogs during frequently sampled intravenous glucose tolerance tests (FSIGTs). Analysis of some data sets from both species resulted in poor identification of parameters. To improve the parameter resolution, the information base on which the parameters are estimated was enlarged. This was accomplished by incorporating into the analysis 1) glucose data obtained between 0 and 8 min of the FSIGT and some of the insulin data obtained prior to the insulin peak and 2) a second set of FSIGT data for each individual obtained during a physiological perturbation. As a result, data analysis was considerably enhanced, with parameter fractional standard deviation being routinely reduced to less than 0.5. Analysis of stimulated data with noise levels for glucose and insulin set between 0.05 and 0.15 confirmed the improvement in parameter estimates. This modified approach to analysis of FSIGTs therefore consistently leads to well-defined kinetic descriptions of experimental data in various situations and supports the usefulness of the minimal model in examining the complex interplay between the parameters that influence overall glucose tolerance.

Effects of epinephrine infusion on determinants of intravenous glucose tolerance in dogs

Effects of four- to fivefold elevations of epinephrine (EPI) on glucose (Glc) metabolism were assessed in eight dogs before and after an intravenous Glc tolerance test, performed 30 min (short EPI) and 72 h (long EPI) after start of EPI infusion. Short EPI increased plasma nonesterified fatty acids (NEFA; 0.46 +/- 0.08 to 0.78 +/- 0.12 mmol/l, P less than 0.05), but Glc and insulin were unchanged. After long EPI, NEFA returned to control but Glc increased from 5.1 +/- 0.1 to 5.7 +/- 0.2 mmol/l (P less than 0.05). EPI reduced overall Glc tolerance (KG) from 3.5 +/- 0.7 to 2.5 +/- 0.2 (short EPI, P less than 0.05) and 2.3 +/- 0.3%/min (long EPI, P less than 0.02). Minimal model analysis showed that short EPI decreased insulin sensitivity (SI) from 7.9 +/- 1.1 to 4.2 +/- 1.2 min-1 per mU/l X 10(-4) (P less than 0.005) and increased pancreatic responsiveness (phi 1 from 3.7 +/- 0.3 to 7.4 +/- 2.9 mU/l.min-1 per mg/dl, P less than 0.025; phi 2 from 2.6 +/- 0.7 to 4.9 +/- 1.2 mU/l.min-2 per mg/dl). After long EPI SI, phi 1, and phi 2 returned to control. In contrast, Glc-mediated Glc disposal (SG) was decreased from 3.5 +/- 0.5 X 10(-2) to 2.8 +/- 0.6 X 10(-2) (short EPI) and 1.3 +/- 0.6 X 10(-2) min-1 (long EPI, P less than 0.02). We conclude that prolonged infusion of EPI leads to adaptation to its acute effects on NEFA, SI, phi 1, and phi 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic actions of cortisol in a macropodid marsupial Thylogale billardierii

In undisturbed pademelon wallabies (Thylogale billardierii) with indwelling jugular venous catheters, an increase in the plasma cortisol concentration from 0.25 +/- 0.05 to 1.35 +/- 0.15 (S.E.M.) mumol/l in 2 h, during i.v. infusion of cortisol at 1.0 mg/kg per h, caused no significant change in the plasma glucose concentration from the control value of 4.26 +/- 0.25 mmol/l. The rates of appearance (Ra) and metabolic clearance (MCR) of glucose, measured by steady-state isotope dilution, also did not change significantly from the control values of 14.9 +/- 0.7 mumol/kg per min and 3.52 +/- 0.19 ml/kg per min respectively. Twice-daily i.m. injections of 7 mg cortisol/kg for 7 days caused increases in plasma concentrations of cortisol, from 0.26 +/- 0.02 to 0.66 +/- 0.04 mumol/l on day 7, and glucose, from 5.1 +/- 0.1 to 7.2 +/- 0.6 mmol/l by day 5. The concentration of glycogen in the liver of wallabies fasted for 24 h increased from the control level of 1.17 +/- 0.56 to 5.92 +/- 1.14 g/100 g on day 7 (P less than 0.01), but mean glucose Ra and MCR did not change significantly. Plasma concentrations of alpha-amino nitrogen rose from 2.73 +/- 0.13 to 3.22 +/- 0.12 mmol/l on day 1 and remained at this level. Plasma concentrations of urea rose from 8.59 +/- 0.62 to 9.70 +/- 0.32 mmol/l on day 1, but then declined below the control level. Food intake and urinary excretion of nitrogen did not change in undisturbed animals. However, fasting followed by liver biopsy was accompanied by urinary excretion of nitrogen in excess of food intake, persisting until day 2 of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Hormonal and metabolic changes during hypothermic coronary artery bypass surgery in diabetic and non-diabetic subjects

Hormonal and metabolic responses to hypothermic coronary artery bypass grafting (CABG) were studied in three groups: 8 non-diabetic patients, 8 patients with non-insulin-dependent diabetes mellitus (NIDDM) given a glucose pump priming solution and 8 NIDDM patients given a non-glucose infusion. There were no significant differences in stress hormone responses between NIDDM and non-diabetic patients, with adrenaline concentrations rising 10-fold, noradrenaline 4-fold and cortisol 2 to 3-fold. Glucagon rose significantly during bypass only in the NIDDM patients who did not receive a glucose prime. Comparable marked hyperglycaemia was seen in both glucose primed groups during bypass and exclusion of glucose from the prime in NIDDM patients prevented this major rise. Postoperatively, the rise in insulin in the glucose primed NIDDM patients contrasted with the slower rise in the non-glucose primed NIDDM patients who were also hyperglycaemic by this stage. Perioperative hyperglycaemia in NIDDM patients undergoing CABG can be prevented by using a non-glucose priming solution and by giving insulin infusion, particularly postoperatively.

Adrenocortical functions in a macropodid marsupial Thylogale billardierii

In a study of adrenocortical functions in macropodid marsupials, measurements were made of the effects of ACTH infusion, ether stress and adrenaline infusion on plasma corticosteroid and glucose concentrations in wallabies (Thylogale billardierii) provided with indwelling venous catheters. The mean plasma total glucocorticoid concentration in undisturbed males and females was 80 +/- 5 (S.E.M.) micrograms/l, of which more than 90% was cortisol. This fraction declined to 68% of the total at the highest ACTH-stimulated concentration of 225 micrograms/l, due to an increase in the contribution by 11-deoxycortisol. Although maximal ACTH stimulation (4.5 i.u./kg per h) caused a five- to sixfold increase in cortisol secretion rate, as measured by isotope dilution during constant-rate tracer infusion, plasma cortisol concentration rose only two- to threefold, due to a marked increase in metabolic clearance. Plasma glucose concentration did not change significantly during either short-term (1 h) i.v. infusion or long-term (8 days) i.m. injection of ACTH, even though plasma cortisol concentration was significantly increased. Ether anaesthesia caused a marked hyperglycaemia that preceded an increase in plasma cortisol concentration and was not sustained while plasma cortisol concentration continued to increase. Infusion of adrenaline i.v. at rates sufficient to cause a similar hyperglycaemia had no significant effect on plasma cortisol concentration. A marked hyperglycaemia during xylazine anaesthesia was not associated with an increase in plasma cortisol concentration and was attributable to suppression of insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of pancreatectomy, tolbutamide and insulin on glucose fluxes in chickens

The effects of pancreatectomy and of injection of insulin or Tolbutamide on glucose fluxes in chickens were examined. This was prompted by earlier observations that Tolbutamide seems not to require the presence of pancreatic insulin for its acute hypoglycaemic action in this species. Rates of appearance (Ra) and disappearance (Rd) of glucose were estimated by isotope dilution using [14C]glucose in single-injection experiments and [14C]glucose and [6-3H]glucose in priming-injection + constant-infusion experiments. Six hours after sub-total pancreatectomy (splenic lobe remained in situ), chickens were hyperglycaemic (16.7 v. 10-4 mmol glucose/1 in controls), had a larger sampled glucose pool (4.41 v. 3.10 mmol) and a higher average rate of glucose utilization (41.7 v. 33.3 micron mol/kg per min) than sham-operated controls as estimated in single-injection experiments. Tolbutamide (50 mg/kg injected i.v.) reduced Ra in intact chickens from 33.9 to 1.1 micro mol/kg per min and reduced Ra in pancreatectomized chickens from 42.2 to 10.2 micro mol/kg per min. in priming-injection + constant-infusion experiments tolbutamide again reduced Ra significantly. In all case Rd tended to fall, apparently as a result of the developing hypoglycaemia. tolbutamide did not affect the volume of extracellular fluid (sucrose space). In single-injection experiments , insulin (1 unit/kg injected i.v.) reduced Ra by 56% and transiently increased Rd by 39%. It was concluded that pancreatectomy and injection of insulin or tolbutamide produce responses in glucose movements in chickens that are qualitatively similar to those in mammals. In chickens the hypoglcaemic action of tolbutamide, which persists in the absence of the pancreas, depends on an inhibition of glucose release by the liver.