Kathleen S. Matt

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Exposure to stress can affect an organism's partitioning of resources among immune function and other organismal functions. However, measuring immune function is often difficult. Recent studies show that the rate of cutaneous wound healing in laboratory rodents is a simple, integrated measure of stress-sensitive immune function. We investigated the use of(More)
The physiologic properties of steroid hormone-binding proteins have been partially characterized in plasmas of 23 avian species (8 orders and 12 families). A specific sex hormone-binding protein (SBP) with high affinity and low capacity, as found in amphibians and some reptiles and mammals, could not be identified in any of the avian species investigated.(More)
Experiments using the dwarf Siberian hamster Phodopus sungorus were carried out to determine possible neuroendocrine consequences of one-time and repeated exposures to 60 Hz magnetic fields (MF). Animals were maintained in either a short-light (SL, 8 h light:16 h dark) or long-light (LL, 16 h light:8 h dark) photoperiod. Acute (one-time, 15 min) exposure of(More)
This study tested the hypotheses that aging is associated with greater hypothalamic-pituitary-adrenal (HPA) axis reactivity to psychological stress, and whether aerobic fitness is associated with a lower HPA axis response to psychological stress. Three groups, consisting of young-unfit women (27.9+/-2.5 yr, n=10), older-unfit women (66.3+/-1.4 yr, n=14),(More)
The number of Leydig cells was determined by stereologic procedures in adult Syrian hamsters housed in long days (14L:10D) to maintain testicular activity (active), in short days (5L:19D) for 12-13 wk to induce testicular regression (photoperiod-induced regressed), or in short days for a period of 21 wk or more to allow spontaneous gonadal recrudescence(More)
The photorefractory period of golden hamsters is characterized by the failure of short daylengths (less than 12.5 hours per 24) to induce gonadal regression. Photorefractoriness is terminated by prolonged exposure to long daylengths (greater than 12.5 hours per 24). This study was designed to determine the precise duration of long day (LD 14 hours light/24)(More)
This study tested the hypotheses that aging is associated with prolonged recovery after a challenge to the hypothalamic-pituitary-adrenal axis (acute exercise) and that aerobic fitness is associated with a blunting of the age-related loss of negative feedback sensitivity. Young (27 +/- 2.8 yr, n = 9), older (64.6 +/- 1.4 yr, n = 11), and older-fit women(More)
Golden (Syrian) hamsters are seasonal breeders. Under natural photoperiodic conditions, their reproductive systems are functional during spring and summer and atrophic during the fall and winter. This reproductive cycle can be duplicated in the laboratory by exposing the animals to artificially-created photoperiods. The endocrine correlates of(More)