Acute effects of exercise on plasma catecholamines in sedentary and athletic women with normal and abnormal menses

Kinin B1 receptor modulates glucose homeostasis and physical exercise capacity by altering adrenal catecholamine synthesis and secretion

Our group has shown in several papers that kinin B1 receptor (B1R) is involved in metabolic adaptations, mediating glucose homeostasis and interfering in leptin and insulin signaling. Since catecholamines are involved with metabolism management, we sought to evaluate B1R role in catecholamine synthesis/secretion. Using B1R global knockout mice, we observed increased basal epinephrine content, accompanied by decreased hepatic glycogen content and increased glucosuria. When these mice were challenged with maximal intensity exercise, they showed decreased epinephrine and norepinephrine response, accompanied by disturbed glycemic responses to effort and poor performance. This phenotype was related to alterations in adrenal catecholamine synthesis: increased basal epinephrine concentration and reduced norepinephrine content in response to exercise, as well decreased gene expression and protein content of tyrosine hydroxylase and decreased gene expression of dopamine beta hydroxylase and kinin B2 receptor. We conclude that the global absence of B1R impairs catecholamine synthesis, interfering with glucose metabolism at rest and during maximal exercise.

Menstrual disorders in athletes

The various menstrual disorders in athletes may reflect different degrees of exposure to a disrupting factor or differences in the susceptibility of various women to disruption. The incidences of these disorders are not well documented, but they appear to be highest in aesthetic, endurance and weight-class sports, and at younger ages, higher training volumes and lower bodyweights. The morbid effects of these disorders include infertility, low bone mass, impaired endothelium-dependent vasodilation, and impaired skeletal muscle oxidative metabolism. The high incidences of menstrual disorders in athletes may derive in part from the self-selection of extraneously affected women into athletics, but many women acquire their menstrual disorders in athletics by failing to adequately increase dietary energy intake in compensation for exercise energy expenditure. Applied research is needed to develop effective dietary interventions that are acceptable to athletes.

Estrogen and substrate metabolism: a review of contradictory research

The increasing number of females participating in physical activity has heightened our awareness of changes in the menstrual cycle which often accompany physical activity. As such, there has been a considerable amount of research investigating the relationships between menstrual cycle changes and bone mineral density, performance, ventilation and substrate metabolism. A number of researchers have concluded that there may be enhanced fat metabolism in eumenorrhoeic versus amenorrhoeic females, or in the follicular phase versus the luteal phase of the menstrual cycle, due to the theoretical estrogen level in eumenorrhoeic versus amenorrhoeic females or the luteal phase versus the follicular phase. However, a definite relationship between resting estrogen level and substrate metabolism has not been clearly established. In addition, the mechanisms which may be responsible for the effect of estrogen on substrate metabolism have not been addressed. It appears that the effects of estrogen on metabolism may be via the effect of estrogen on glucogenic hormones or lipolytic enzymes. Therefore, the primary purpose of this review is to explore the effects of estrogen on substrate metabolism. Menstrual cycle physiology and possible mechanisms for the effects of estrogen on metabolism, as well as previous research on estrogen and metabolism in rats and humans, will be discussed.

Effects of a training program on resting plasma 2-hydroxycatecholestrogen levels in eumenorrheic women

Catecholestrogens (CE) represent a major metabolic pathway in estrogen metabolism. Previous information on CE and training is limited to two cross-sectional studies that did not involve standardized training. Our purpose, by means of a prospective design, was to evaluate the effects of a brief, exhaustive training program on resting plasma concentrations of 2-hydroxy CE. The experimental design spanned two menstrual cycles; a control cycle and a training cycle. The subjects were nine previously untrained, eumenorrheic women [body fat: 24.8 +/- 1.0 (SE) %]. Data were collected during the follicular (FPh) and the luteal phases (LPh). Posttraining FPh and LPh tests were held the day after the last day of a 5-day period of training on a cycle ergometer. Total 2-hydroxyestrogens (2-OHE) averaged 200 +/- 29 pg/ml during the FPh and 420 +/- 54 pg/ml during the LPh (P < 0.05). Levels of total 2-methoxyestrogens (2-MeOE) were 237 +/- 32 pg/ml during the FPh and 339 +/- 26 pg/ml during the LPh (P < 0.05). After training, although the plasma levels of 2-OHE significantly decreased (21%; P < 0.05) during the LPh, the actual CE formation (as estimated from the 2-OHE-to-total estrogens ratio) increased (+ 29%; P < 0.05). CE activity, as expressed by the 2-MeOE-to-2-OHE ratio, showed significantly higher values in both phases (FPh, + 14%; LPh, + 13%; P < 0.05). At the same time, resting levels of norepinephrine (NE) were increased by 42% (P < 0.05). CE strongly inhibit biological decomposition of NE by catechol-O-methyltransferase (COMT). Results of the present study suggest that, in response to training, CE are increasingly competing with the enzyme COMT, thus preventing premature NE deactivation.

The female athlete

Since the passage of Title IX in 1972, women's participation in physical activity and sports has increased significantly. A concurrent expansion in the body of knowledge regarding women and sports has occurred. Questions regarding menstrual dysfunction and exercise continue, while new questions about menstrual dysfunction and its effect on bone mineral density have arisen. Physical and physiological differences between men and women not only guide treatment, but help fuel policy decisions regarding competition between males and females. It is essential for the physical therapist to remain current on issues related to women and sports in order to better advise and treat the female athlete.

Dysfunctional uterine bleeding

Dysfunctional uterine bleeding (DUB) is a common gynecologic problem, occurring most frequently at the extremes of a woman's reproductive life. The primary cause of DUB is anovulation; however, because DUB is a diagnosis of exclusion, a detailed history and a thorough physical and pelvic examination with appropriate diagnostic tests are essential in order to rule out other pathologic causes of abnormal uterine bleeding. Knowledge of the physiologic basis, differential diagnoses, and diagnostic and management modalities for DUB enables the nurse practitioner to provide optimal care for the patient.

Preserved atrial natriuretic peptide secretory function after cardiac transplantation

The purpose of this investigation was to determine whether atrial natriuretic peptide (ANP) secretory function is preserved after cardiac transplantation. Thirteen hemodynamically stable outpatients performed supine exercise on a bicycle an average of 7 months after orthotopic cardiac transplantation. Right atrial pressure increased 2.2-fold (6 +/- 1 to 13 +/- 2 mm Hg) and pulmonary artery wedge pressure 2.1-fold (11 +/- 1 to 23 +/- 7 mm Hg) with exercise in the transplant recipients. Resting venous ANP level (114 +/- 19 pg/ml) and peak exercise venous level (373 +/- 61 pg/ml) was elevated in transplant recipients (p less than 0.001) compared with control subjects (21 +/- 1 and 92 +/- 14 pg/ml, respectively. This represents a 3.3-fold (114 +/- 19 to 373 +/- 61 pg/ml) increase in the ANP level from resting to exercise in transplant recipients and a 4.4-fold (21 +/- 1 to 92 +/- 14 pg/ml) increase in control subjects. A correlation between venous ANP levels and hemodynamics (right atrial pressure) was observed r = 0.49 p = 0.01. It is concluded that ANP levels at rest are elevated after cardiac transplant, the levels correlate with the intracardiac hemodynamics, and exercise-induced augmentation of plasma levels occurs.

Managing abnormal vaginal bleeding

Abnormal vaginal bleeding is a diagnostic and therapeutic challenge. A carefully directed patient history and physical examination along with basic laboratory tests can lead to accurate diagnosis. In most cases, symptoms can be controlled with use of oral contraceptives, progesterone supplements, and/or nonsteroidal anti-inflammatory drugs.

Influence of positive inotropic therapy on pulsatile hydraulic load and ventricular-vascular coupling in congestive heart failure

The aortic input impedance spectrum provides a description of the total hydraulic load imposed on the left ventricle and may be used to assess the coupling of the ventricle to the vasculature. The adaptation of the vasculature to positive inotropic intervention was examined in 10 patients with idiopathic dilated cardiomyopathy to test the hypothesis that increased myocardial contractility is matched by complementary changes in aortic impedance that optimize ventricular-vascular coupling and maximize power transfer to the circulation. High fidelity intravascular recordings of aortic pressure and flow were obtained at baseline study and during infusion of dobutamine to derive the aortic input impedance spectrum. In eight patients in whom increased staged infusion of dobutamine resulted in a significant increase in stroke volume (22.3 +/- 14.5 ml/beat increase over baseline), the significant (p less than 0.05) increase in the maximum of the first derivative left ventricular pressure pulse (dP/dt) was accompanied by significant decreases in characteristic impedance of the aorta (138 +/- 88 to 92 +/- 44 dyne.s.cm-5) wave reflection index (238 +/- 144 to 109 +/- 59 dyne.s.cm-5), and low frequency moduli of impedance. Effective positive inotropic therapy with dobutamine in the setting of congestive heart failure is accompanied by complementary changes in the aortic impedance spectrum, which represent a matching of impedance to the increased contractile state of the ventricle and facilitation of ventricular-vascular coupling.

Anorexia nervosa, athletics, and amenorrhea

Menstrual dysfunction is common in adolescents who are involved in intensive athletic activity or who are limiting their nutritional intake excessively. The mechanism for hypothalamic amenorrhea in athletes and dieters is not yet fully understood. Other causes of menstrual dysfunction due to pregnancy, central lesions, hormone imbalance, or ovarian failure should be excluded in the athlete with amenorrhea. Amenorrheic patients who have sufficient estrogen effect on their endometrium to have withdrawal bleeding following exposure to progestins should be cycled with progestins on a regular basis to prevent endometrial hyperplasia. Estrogen replacement with cyclic progestin should be considered in the hypoestrogenic adolescent with prolonged amenorrhea. The long-term consequences of hypothalamic amenorrhea in adolescents remain to be determined.