This investigation was designed to evaluate the production rates and concentrations of salivary alpha-amylase as a measure of adrenergic activity under several conditions of stress in human subjects. Saliva and blood samples were simultaneously collected from men at four 15 min intervals both before and after regimens for exercise, a written examination, or a rest period. The regressions of salivary alpha-amylase on plasma norepinephrine (NE) concentrations were significant for both exercise (P < 0.001) and examination (P < 0.01) protocols. Aerobic exercise induced a 3-fold mean increase in alpha-amylase; both NE and epinephrine (EP) increased approximately 5-fold over control levels. Levels of alpha-amylase and NE returned to control levels within 30-45 min after exercise, but EP remained elevated by approximately 2-fold during the remaining hour of observation. During the written examination, alpha-amylase and NE, but not EP, concentrations increased in parallel. In further studies the effects of exercise and exposure to heat and cold on the relationship of salivary alpha-amylase to heart rate and body temperature were investigated. Greater intensities of exercise were associated with greater increases in alpha-amylase concentrations. During heat exposure in a sauna (66 degrees C for 40 min) amylase, heart rate and body temperature all increased progressively. However, during exposure to cold (4 degrees C for 40 min) amylase increased rapidly, though heart rate and body temperature remained unchanged. Salivary cortisol concentrations were unchanged during exposure to heat or cold. We conclude that salivary alpha-amylase concentrations are predictive of plasma catecholamine levels, particularly NE, under a variety of stressful conditions, and may be a more direct and simple end point of catecholamine activity than are changes in heart rate.

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BackgroundPersistent pollutants, such as polychlorinated biphenyls (PCBs), affect endocrine function. Human exposure to polybrominated diphenyl ethers (PBDEs), which are similar in structure to PCBs, has increased recently, but health effects have not been well studied.ObjectivesOur goal in this study was to determine whether PBDE body burdens are related to thyroid and steroid hormone levels, thyroid antibodies, and thyroid disease in a cohort of frequent and infrequent adult male sport fish consumers.MethodsWe tested serum from 405 adult males for PBDE congeners, PCB congeners, testosterone, sex-hormone–binding globulin (SHBG), SHBG-bound testosterone, thyroglobulin antibodies, and the thyroid hormones thyroxine (T4), triiodothyronine (T3), thyroid-stimulating hormone (TSH), and T4-binding globulin (TBG). We collected data on demographics, fish consumption, medical diseases, and medication use.ResultsThe median sum of PBDEs was 38 ng/g lipid. In 308 men without thyroid disease or diabetes, PBDEs were positively related to measures of T4 and reverse T3 and inversely related to total T3 and TSH. PBDEs were positively related to the percentage of T4 bound to albumin, and inversely related to the percentage of T4 bound to TBG. Associations of BDE congeners with hormones varied. BDE-47 was positively associated with testosterone levels. Participants with PBDEs over the 95th percentile were more likely to have thyroglobulin antibodies, although high PBDE exposure was not associated with thyroid disease. PBDE effects were independent of PCB exposure and sport fish consumption.ConclusionsPBDE exposure, at levels comparable with those of the general U.S. population, was associated with increased thyroglobulin antibodies and increased T4 in adult males.

This study reports the temporal pattern of milk output in 2 groups of lactating mothers during the first 6 weeks postpartum. A study aim was to examine if the average milk output for postpartum days 6 and 7 (baseline) predicts milk adequacy at week 6 postpartum. Mothers of preterm (< or = 31 weeks) infants (n = 95) used mechanical expression to initiate and maintain their milk supply; mothers of a singleton healthy term infant (n = 98) fed their infant at the breast. Baseline milk output was predictive of milk adequacy, defined as > or = 500 mL/d at week 6 (P = .000). Preterm mothers were 2.81 times more at risk of not producing adequately than term mothers were. Study findings suggest that interventions that promote the initiation and maintenance of an adequate milk supply during the first week postbirth are critical.