by Kwok-fung Wong. / Bibliography: leaves 92-102 / Thesis (M.Phil.)--Chinese University of Hong Kong, 1982

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Oxytocin is a neurohormone that has been correlated with lactation, uterine-contractions, postpartum behavior, pro-social behavior, trust, empathy, and decreased anxiety. In addition, oxytocin is believed to underscore the tend-and-befriend response to stress. In this study, adrenocorticotropic hormone (ACTH), cortisol and oxytocin levels were measured in response to a social stressor in human participants. Oxytocin was initially seen to increase with ACTH and cortisol in response to a social stressor. As levels of oxytocin increase, levels of ACTH and cortisol were shown to decrease or plateau. I conclude that oxytocin is released in response to a perceived stressor and display inhibitory effects over ACTH and cortisol.

by Pik-ying Ng. / Bibliography: leaves 106-117 / Thesis (M.Phil.)--Chinese University of Hong Kong, 1983

The purpose of the present study was to test the acute effects of a dietary supplement, having as its major ingredient an extract of ginseng, on grip strength, lower body power output, cardiovascular markers, metabolic markers, hormones, and mood state. Twelve experienced resistance-trained men (28.3 ± 5.7 yrs) were randomly administered placebo (P), single dose (SD) and double dose (DD) of the supplement on separate days. Diet and activity levels were kept constant across testing days. On each day, subjects began with the Profile of Mood States (POMSpre1), blood draws (BDpre1), blood pressure (BPpre1), and heart rate (HRpre1) assessments, then ingested the drink and sat quietly for 30 minutes. BDpre2, BPpre2, and HR pre1 were then taken. Subjects performed the grip strength and cycle ergometer tests followed immediately by BDpost, HRpost, and BPpost and POMSpost. The testing session ended with blood draws, heart rates, and blood pressures being taken 30 (post30), 60 (post60), 120 (post120) and 180 (post180) minutes post exercise. Grip strength did not differ between P, SD, or DD treatments. Cycle ergometry peak power (PP), average power (AP) and total work (TW) were significantly higher for the SD and DD than P; however, no significant difference existed between SD and DD treatments. For LH and T significant differences were found among all treatment conditions. There were no significant treatment effects for HR, BP, glucose, insulin, lactate, GH or PRL or for the POMS. There was a significant treatment*time interaction for ACTH (p < .05). Post hoc analysis indicated that at Tpost ACTH was significantly lower for D treatment vs P or S treatments (p < .05) and at Tpost60 ACTH was significantly lower for S and D treatments vs P treatment (p < .05). There was significant differences in C between the D treatment (260.45 ± 15.58 nmol•L-1) and the P (336.08 ± 27.59 nmol•L-1) and S (311.14 ± 21.01 nmol•L-1) treatments (p < .001). There was a significant difference for T:C ratio values among P (0.0810 ± 0.0090), S (0.0960 ± 0.0130) and D (0.1410 ± 0.0190) treatments (p < .001). Acute ingestion of a polynutrient supplement containing a standardized ginseng tract, was able to increase PP, AP, TW LH, and testosterone and decrease ACTH and cortisol. No significant effects were found for GH, PRL, insulin, glucose, lactate, HR, BP or POMS scores. Acute ingestion of a polynutrient supplement was able to increase performance and the anabolic environment in resistance trained men.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 106-114).

Studies described in this thesis were performed to investigate associations among season, diet, pituitary pars intermedia dysfunction (PPID) and blood concentrations of adrenocorticotropic hormone (ACTH), insulin, glucose, and leptin in horses. In the first study, higher ACTH concentrations were detected in horses affected with PPID. A seasonal increase in plasma ACTH concentration was detected in the late summer and early fall, but PPID did not affect the timing or duration of this increase. Pasture grazing raised glucose and insulin concentrations with a peak in September, at the same time that horses had higher ACTH concentrations, and this convergence of risk factors may raise the risk of laminitis. All of the horses included in this study were from the same farm. The second study was performed to determine whether horses from different locations within the same region exhibited the same seasonal increase in ACTH concentrations. Results of this study indicate that the seasonal increase in plasma ACTH concentrations occurs in horses from different farms with varying management practices. The third study investigated the effects of season on plasma leptin concentrations in the horses from the first study. We hypothesized that higher leptin concentrations would be detected in advance of the seasonal increase in plasma ACTH concentrations. Results did not support our hypothesis because leptin concentrations increased after ACTH concentrations peaked in September. Our findings suggest that the seasonal increase in ACTH concentrations induced leptin resistance, which might facilitate weight gain in the autumn. Alternatively, leptin concentrations increased as a result of weight gain or change in body fat composition. In summary, season appears to signal upregulation of the hypothalamic-pituitary-adrenal axis in horses, in an effort to prepare for winter. This upregulation is retained in horses with PPID, a disorder associated with loss of dopaminergic inhibition to the pars intermedia of the pituitary. The seasonal rise in plasma ACTH concentrations is followed by an increase in leptin concentrations, which suggests the development of leptin resistance or an increase in adiposity.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 106-118).

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 80-97).

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