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Biomedical subjects

F E Chang

Publications and source records attributed to F E Chang.

10 recordsLinked to original sources
PubMed1987

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

Norepinephrine plays a role in the regulation of luteinizing hormone secretion and may therefore be involved in the etiology of exercise-induced menstrual dysfunction. This study evaluated both intraexercise and postexercise responses of epinephrine, norepinephrine, and dopamine in sedentary women and women runners with normal and abnormal menstruation. Five eumenorrheic nonrunners and five eumenorrheic, four oligomenorrheic, and five amenorrheic runners were evaluated on 2 consecutive days. On day 1, the women cycled on a bicycle ergometer against an increasing work load until exhaustion, and on day 2, the women underwent a submaximal exercise regimen. Serial blood draws were taken at specified time intervals during intraexercise and postexercise periods on both days. The data collected during exercise for all groups showed that epinephrine and norepinephrine had a sixfold to sevenfold rise on day 1 and had a threefold rise on day 2. Dopamine increased twofold during both exercise protocols. On day 1 norepinephrine displayed a significantly higher percentage change from baseline to peak levels for oligomenorrheic and amenorrheic runners than for eumenorrheic runners and sedentary women. This latter finding is consistent with the hypothesis that periodic marked elevations in norepinephrine levels during maximal exercise may interfere with pulsatile luteinizing hormone release and hence may play a role in the occurrence of menstrual dysfunction in women runners.

Adult↗
PubMed1986

The acute effects of exercise on prolactin and growth hormone secretion: comparison between sedentary women and women runners with normal and abnormal menstrual cycles.

Acute exercise may stimulate PRL secretion, which, in turn, may contribute to exercise-associated menstrual dysfunction. We compared the response of PRL secretion in sedentary women and women runners with normal and abnormal menstrual cycles. We also studied the GH response to acute exercise, as GH may bind to lactogenic receptors. Five nonrunning women, 5 eumenorrheic running women, four oligomenorrheic running women, and six amenorrheic running women were studied on 2 consecutive days. On day 1, the women cycled on a bicycle ergometer against an increasing workload until total exhaustion. Serum PRL and GH increased several-fold in response to acute exercise in all three groups of running women. On day 2, the women simulated a daily training run by enduring a designed submaximal exercise regimen. In response to submaximal exercise, no group had a significant elevation of PRL or GH. Therefore, a threshold of exercise intensity exists that must be achieved before a significant increase in PRL or GH secretion occurs in women runners; serum PRL and GH in the nonrunning group did not increase significantly even in response to acute maximal exercise. The transient elevations in PRL and GH in women runners probably do not contribute to their menstrual dysfunction unless individual hypersensitivity of the hypothalamic-pituitary-ovarian axis to such intermittent elevations is present.

Adult↗
PubMed1985

Serum carotene levels in female long-distance runners.

Hypercarotenemia has been associated with anorexia nervosa and hypothalamic amenorrhea. With the emergence of a spectrum of menstrual dysfunction, including anovulation in women runners, the hypothesis of hypothalamic amenorrhea in these patients has been formulated. Other authors have proposed exercise-associated amenorrhea to be distinct from hypothalamic amenorrhea based on endocrine profiles. Using carotene as an index test of hypothalamic amenorrhea, we have studied female long-distance runners (greater than 25 miles/week) and have found no difference in the carotene levels between ovulatory (midfollicular) and anovulatory runners. These data support other evidence that exercise-associated amenorrhea is distinct from hypothalamic amenorrhea.

Adult↗
PubMed1984

Chronic anovulation.

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Adrenocortical Hyperfunction↗
PubMed1984

Twenty four-hour prolactin profiles and prolactin responses to dopamine in long distance running women.

Long distance women runners have a high incidence of oligoamenorrhea. In order to study the possible role of PRL in contributing to their menstrual dysfunction, we evaluated PRL secretion in eumenorrheic (n = 7) and oligomenorrheic runners (n = 9) who averaged 25-50 miles/week, as well as nonrunning women (n = 5) during the midfollicular phase of their cycles. Serum estradiol, progesterone, testosterone, FSH, LH, TSH, and T4 were similar among the three groups. The mean 24-h +/- SE PRL concentrations between the three groups: nonrunners, 12.9 +/- 0.6 ng/ml; eumenorrheic runners, 13.5 +/- 0.4 ng/ml; and oligomenorrheic runners, 15.0 +/- 0.8 ng/ml, were not significantly different. A dopamine (DA) infusion, 0.004 micrograms/kg X min, produced physiologic serum DA levels in these subjects. The nadir of serum PRL levels during DA infusion was similar in each group, which argues against an abnormality in dopaminergic tone in the runners with menstrual dysfunction. Our findings of normal 24-h PRL secretion and appropriate PRL responses to DA in women runners with menstrual dysfunction do not support a role for PRL in this disorder.

Adolescent↗
PubMed1983

Hyperlactacidemia associated with acute ritodrine infusion.

The use of beta-mimetic tocolytics has been associated with various metabolic derangements which have been the topic of investigational reports. Lactic acidosis has been reported to follow concomitant steroid administration. The purpose of this investigation was to delineate more clearly hyperlactacidemia in patients receiving various tocolytics with and without concomitant use of steroids in a prospective manner. Twenty patients in premature labor who received ritodrine had markedly increased blood levels of lactate (baseline, 1.0 +/- 0.1 mmol/L [SEM] versus 3.5 +/- 0.3 mmol/L [SEM] after 6 hours' intravenous infusion). In the other treatment groups, ritodrine plus hydrocortisone, hydrocortisone alone, and magnesium sulfate alone, lactate levels failed to change significantly. Clinical relevance and implications for metabolic alterations associated with beta-mimetic tocolysis are discussed.

Acidosis↗
PubMed1981

Management of the uncomplicated postdate pregnancy.

The management of a postdate (greater than 42 weeks) pregnancy with no apparent complication is often unclear. This study compares the intrapartum courses and perinatal outcomes between 101 postdate pregnancies and 322 term pregnancies. The mean maternal age, race, parity and type of care service were not significantly different between the two groups. Signs of fetal compromise were also not different, but a large fetus was more common (p less than 0.01) in the postdate pregnancies (16 cases). The need for cesarean section (13 cases) or midforceps manipulation (7 cases) was increased fourfold in the postdate over the term pregnancies (p less than 0.05). Meconium during labor was not more common in the postdate pregnancies, but the one postdate perinatal death occurred in the neonatal period from severe meconium aspiration complications. A postdate pregnancy with no apparent complications may safely be observed closely.

Adult↗