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Endogenous Hormones (endogenous + hormones)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2008
Geoffrey C. Kabat
Abstract Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40,59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95% confidence interval 0.73,0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose,response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association. © 2007 Wiley-Liss, Inc. [source]

Weight control and physical activity in cancer prevention

OBESITY REVIEWS, Issue 1 2002
Franca Bianchini
Summary Overweight and obesity have reached epidemic dimensions worldwide, mainly due to consumption of high energy diets and increased sedentary behaviour. Overweight and insufficient physical activity are clearly associated with cardiovascular diseases and type 2 diabetes. Evidence is also accumulating that they may also increase cancer risk, particularly in the colon, breast and endometrium. This effect seems to be mediated by alterations in the metabolism of endogenous hormones, including sex steroids and insulin, and levels of insulin-like growth factor(IGF)-I and IGF-binding proteins. In light of the beneficial effects of weight control and physical activity for cancer prevention, a healthy lifestyle, keeping a low body weight and exercising most days of the week, is recommended. [source]

Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men

THE JOURNAL OF PHYSIOLOGY, Issue 21 2009
Daniel W. D. West
We aimed to determine whether exercise-induced elevations in systemic concentration of testosterone, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) enhanced post-exercise myofibrillar protein synthesis (MPS) and phosphorylation of signalling proteins important in regulating mRNA translation. Eight young men (20 ± 1.1 years, BMI = 26 ± 3.5 kg m,2) completed two exercise protocols designed to maintain basal hormone concentrations (low hormone, LH) or elicit increases in endogenous hormones (high hormone, HH). In the LH protocol, participants performed a bout of unilateral resistance exercise with the elbow flexors. The HH protocol consisted of the same elbow flexor exercise with the contralateral arm followed immediately by high-volume leg resistance exercise. Participants consumed 25 g of protein after arm exercise to maximize MPS. Muscle biopsies and blood samples were taken as appropriate. There were no changes in serum testosterone, GH or IGF-1 after the LH protocol, whereas there were marked elevations after HH (testosterone, P < 0.001; GH, P < 0.001; IGF-1, P < 0.05). Exercise stimulated a rise in MPS in the biceps brachii (rest = 0.040 ± 0.007, LH = 0.071 ± 0.008, HH = 0.064 ± 0.014% h,1; P < 0.05) with no effect of elevated hormones (P= 0.72). Phosphorylation of the 70 kDa S6 protein kinase (p70S6K) also increased post-exercise (P < 0.05) with no differences between conditions. We conclude that the transient increases in endogenous purportedly anabolic hormones do not enhance fed-state anabolic signalling or MPS following resistance exercise. Local mechanisms are likely to be of predominant importance for the post-exercise increase in MPS. [source]

Endocrine Aspects of Female Sexual Dysfunction

THE JOURNAL OF SEXUAL MEDICINE, Issue 1 2004
Susan R. Davis MD
ABSTRACT Introduction., Various endogenous hormones, including estrogen, testosterone, progesterone and prolactin, may influence female sexual function. Aim., To provide recommendations for the diagnosis and treatment of women with endocrinologic sexual difficulties. Methods., The Endocrine Aspects of Female Sexual Dysfunction Committee was part of a multidisciplinary International Consultation. It included four experts from two countries and several peer reviewers. Main Outcome Measure., Expert opinion was based on committee discussion, a comprehensive literature review and evidence-based grading of available publications. Results., The impact of hormones on female sexual function and their etiological roles in dysfunction is complex. Research data are limited as studies have been hampered by lack of precise hormonal assays and validated measures of sexual function in women. Sex steroid insufficiency is associated with urogenital atrophy and may also adversely affect central sexual thought processes. Systemic estrogen/estrogen progestin therapy alleviates climacteric symptoms but there is no evidence that this therapy specifically improves hypoactive sexual desire disorder (HSDD) in premenopausal or postmenopausal women. Exogenous testosterone has been shown in small randomized controlled trials (RCT) to improve sexual desire, arousal and sexual satisfaction in both premenopausal and postmenopausal women. However, as there is no biochemical measure that clearly identifies who to treat, use of exogenous testosterone should be considered only after other causes of HSDD have been excluded, such as depression, relationship problems and ill health. The clinical assessment of HSDD should include detailed medical, gynecologic, sexual and psychosocial history and physical examination including the external/internal genitalia. Hormonal therapy should be individualized and risks/benefits fully discussed, and all treated women should be carefully followed up and monitored for therapeutic side effects. Conclusions., There is a need for prospective, multi-institutional clinical trials to define safe and effective endocrine treatments for female sexual dysfunction. [source]