Effects of hormone replacement on growth hormone and prolactin exercise responses in postmenopausal women

Kraemer, Robert R.; Johnson, Lisa G.; Haltom, R.; Kraemer, G. R.; Gaines, H. E.; Drapcho, M.; Gimple, T.; Castracane, V. Daniel

doi:10.1152/jappl.1998.84.2.703

Cited by 29 publications

(21 citation statements)

References 31 publications

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“…Most studies have reported a transient increase in prolactin directly following exercise, which returns to normal within 1 day (9-12, 14-16). This pattern has been observed in both fit and sedentary individuals (10,(13)(14)(15)(16). Acute exercise exerts physical stress on the body, such as increasing heart rate and hypoxia (21), which can, in turn, increase prolactin levels.…”

Section: Discussionmentioning

confidence: 92%

“…In two studies, prolactin concentrations increased when participants completed a maximal exercise test, but not when completing a submaximal test (10,14). Two studies have examined postmenopausal women, and both reported that intense acute exercise increased prolactin concentrations (15,16). To our knowledge, however, no data are available concerning the relation between long-term physical activity and prolactin levels, particularly in postmenopausal women who are at high risk for breast cancer.…”

Section: Introductionmentioning

confidence: 99%

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Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women

Tworoger

Sorensen

Chubak

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Prolactin is associated with an increased risk of postmenopausal breast cancer; however, few modifiable factors are known to reduce prolactin concentrations. Therefore, we examined the effect of a 12-month moderate-intensity exercise intervention on serum prolactin concentrations as a secondary end point (primary end points were estrogens and androgens). We randomly assigned 173 postmenopausal women who were sedentary, overweight (body mass index >24 kg/m 2 , body fat >33%), ages 50 to 75 years, and not using hormone therapy to an exercise intervention or stretching control group. The intervention was facility-and homebased (45 min, 5 days/wk moderate-intensity sports/recreational exercise). One hundred and seventy (98%) women completed the study. Prolactin concentrations were similar at baseline (P = 0.25, geometric mean exercisers = 6.9 and controls = 7.5 ng/mL). Overall, the intervention was not associated with changes in prolactin concentrations between exercisers and controls at 3 months (P = 0.46) or 12 months (P = 0.29). The intervention effect did not vary by baseline age, body mass index, parity, or change in percent body fat during the intervention. Among exercisers, there was a significant difference in prolactin concentrations by change in fitness (VO 2 max) between baseline and 12 months. Exercisers whose VO 2 max changed by <5% had a 5% increase in prolactin concentrations, whereas those who increased their VO 2 max by 5% to 15% and >15% had a 11% (P = 0.03) and 7% (P = 0.01) decrease in prolactin concentrations, respectively. Although the exercise intervention had little effect on prolactin concentrations overall, increasing physical fitness was associated with reduced prolactin concentrations among postmenopausal women. (Cancer Epidemiol Biomarkers Prev 2007;16(5):895 -9)

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women

Tworoger

Sorensen

Chubak

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…Endurance exercise has been shown to stimulate an increase in growth hormone (Copeland, Consitt, & Tremblay, 2002;Kraemer, Johnson, et al, 1998;Sidney & Shephard, 1977) and DHEA(S) (Johnson et al, 1997) in older women. There is no evidence that endurance exercise increases levels of IGF-I or testosterone in older women (Chadan, Dill, Vanderhoek, & Parkhouse, 1999;Copeland et al).…”

Section: Exercise-intervention Studies-acute Responsesmentioning

confidence: 99%

“…Poehlman and colleagues did find a significant increase in IGF-I in their male participants and suggested that this gender-dimorphic response was explained by the lowered estrogen levels in their older female participants. Estrogen-replacement therapy has been shown to augment the growth-hormone (Kraemer, Johnson et al, 1998) and DHEA (Johnson et al, 1997) responses to exercise, and therefore it is conceivable that estrogen-replacement therapy would have an effect on the response to longterm training, as well. To date no research has addressed this issue.…”

Section: Exercise-intervention Studies-chronic Adaptationsmentioning

confidence: 99%

Aging, Physical Activity, and Hormones in Women—A Review

Copeland

Chu²,

Tremblay³

2004

Journal of Aging and Physical Activity

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Women experience significant changes in endocrine function during aging. Decreasing levels of anabolic hormones may be associated with musculoskeletal atrophy and decrease in function that is observed in older women and, as a result, there has been an increase in the use of pharmacological hormone therapies. It is difficult to distinguish, however, between physiological changes that are truly age related and those that are associated with lifestyle factors such as physical activity participation. Some research has shown that circulating levels of anabolic hormones such as DHEA(S) and IGF-I in older women are related to physical activity, muscle function, and aerobic power. Exerciseintervention studies have generally shown that increasing age blunts the acute hormonal response to exercise, although this might be explained by a lower exercise intensity in older women. There have been relatively few studies that examine hormonal adaptations to exercise training. Physical activity might have an effect on hormone action as a result of changes in protein carriers and receptors, and future research needs to clarify the effect of age and exercise on these other components of the endocrine system. The value and safety of hormone supplements must be examined, especially when used in combination with an exercise program. Key Words: exercise, fitness, hormone-replacement therapyThere is a decline in physical well-being with advancing age, which includes an increase in body fat, loss of muscle mass and bone density, and a decrease in strength and functional capacity. This decline in well-being coincides with significant changes in the endocrine system, and it has been recognized that many of the symptoms associated with aging are similar to those observed in young adults with hormone deficiencies. For example, growth-hormone deficiency in young adults and adolescents results in an increase in body fat and decrease in muscle mass (Hulthen et al., 2001). There are three main hormone systems that show significant changes with age: the gonadal hormones (menopause and andropause); the main

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“…Only one study has examined the exercise-induced GH responses in women on HRT and reported that the exercise-induced integrated GH levels were higher in women using HRT (6). These authors, however, did not examine whether the magnitude of the exerciseinduced GH response or the GH secretory pulsatility were different between HRT users and non-users.…”

Section: Introductionmentioning

confidence: 99%

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

et al. 2005

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Objective: This study examined the effect of hormone-replacement therapy (HRT) use on the incremental GH response to aerobic exercise in postmenopausal women and established whether racial differences in the GH response were seen at rest and in response to exercise. Methods: 13 white (n ¼ 6, HRT; n ¼ 7, no HRT) and seven black women (no HRT) were studied on two occasions, a control day and an exercise day (30 min at 70% VO 2 max on a cycle ergometer). Blood was sampled every 10 min for a 4-h period and analyzed for GH using an ultrasensitive chemiluminescent assay. Results: The mean 4-h GH concentration was higher on both study days in the HRT women than the non-HRT users. The integrated GH concentrations were greater in the HRT women both at rest and in response to exercise (rest, 352^53 min mg l 21; exercise, 711^57 min mg l 21; P , 0.01) than in the non-HRT women (rest, 157^87 min mg l 21; exercise, 248^94 min mg l 21 ). The incremental GH response was greater in the HRT users than in the non-HRT women (358^130 versus 90.8^94 min mg l 21 , respectively; P , 0.05). GH-production rate during the 4-h period was greater in the HRT women than in the non-HRT women (P , 0.01), due to an increase in the GH mass secreted/pulse (P , 0.05), with no change in GH pulse number or GH half-life. No racial differences in the mean 4-h GH concentrations or integrated GH concentrations were found at rest or in response to exercise. Conclusion: HRT use resulted in a greater incremental exercise response compared with non-HRT users, due to changes in the secretory pulse characteristics in the HRT users. This study also demonstrated that no racial differences exist at rest and in response to exercise in the morning hours.

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Effects of hormone replacement on growth hormone and prolactin exercise responses in postmenopausal women

Cited by 29 publications

References 31 publications

Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women

Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women

Aging, Physical Activity, and Hormones in Women—A Review

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

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