Neuroendocrine adaptive responses to psychological stress include activation of the hypothalamic-pituitary-adrenal (HPA) axis and sometimes suppression of the hypothalamic-pituitary-gonadal (HPG) axis. In women who experience chronic stress, these responses are probably responsible for disturbances in the menstrual cycle. In the present experiment, we investigated the effect of an acutely stressful situation on the physiological and neuroendocrine responses in college age women. We hypothesized that females who are experiencing some degree of abnormal menstrual function or women who have less-robust cycles (oligomenorrheic females) would exhibit differences in gonadotropin secretion from eumenorrheic females when exposed to psychological stressors. Fifteen women completed this study: eumenorrheic (n = 5) and oligomenorrheic women (n = 5) who experienced a series of psychological stressors, and eumenorrheic controls (n = 5). Blood samples were taken at 10 min intervals for 8 h (09:00-17:00) in each woman during the mid-follicular phase of the menstrual cycle. The psychological stressors were administered for 1 h beginning at 13:00 h. Luteinizing hormone (LH), growth hormone (GH) and cortisol were measured in each sample to assess the effect of stress on secretion of these hormones. Deconvolution analysis was used to analyze pulsatile hormone secretion and the approximate entropy (ApEn) statistic analyzed the regularity of release of each hormone. Although, there were significant changes in heart rate (HR), skin resistance (SR) and cortisol levels in the stressed women during the psychological stressor compared to resting baseline values but not in the controls, there was no difference in either LH or GH secretion between women who experienced stress and those who did not. Furthermore, there were no differences in the LH or GH secretion patterns in the oligomenorrheic and eumenorrheic women exposed to the psychological stressor.

When energy intake is restricted in mammals, there are neuroendocrine adjustments in the secretion of reproductive and metabolic hormones to reallocate energy for vital functions. In the present study, we investigated whether there were differences in the luteinising hormone (LH), growth hormone (GH) and cortisol responses to a 48-h fast in adult gonad-intact male and female rhesus macaques. In both male and female macaques, blood glucose levels were significantly lower in fasted than in control studies, and levels were higher in males than in females. Male rhesus monkeys had significantly lower (P < 0.01) mean serum LH levels after a 48-h fast than under fed conditions and this was attributable primarily to a decrease in the amount of LH released during each secretory episode. In fasted females, serum LH levels were significantly greater (P < 0.05) than during the fed conditions but no differences were found in pulse amplitude or in the number of pulses. Almost twice as many GH pulses were observed in both males and females during fasting but there was no difference in either mean serum GH levels or pulse amplitude between control and fasted studies. A typical diurnal profile in cortisol levels was observed in both sexes and both experimental conditions. Under control conditions, male macaques released less cortisol than females, and although fasting increased mean cortisol levels in both males and females, only the males shown a significant rise over levels observed in control studies. The changes in plasma LH and cortisol levels in fasted rhesus macaques are similar to those observed in humans and suggest that gonadotrophin and corticotrophin secretion are more resistant to short-term energy deprivation in female than in male primates.

Stress research has gained popularity due to the increased acknowledgement of chronic stress on personal health. With this increased interest, researchers need to assure that the public receives quality, evidence-based solutions. Improvements following a stress reduction intervention are generally assessed by a self-survey pre-post rather than objective biomarkers of stress. There is a need in the literature for a research paradigm utilizing two different stressors to prevent any alteration in post-intervention results due to habituation of the stressor. The Trier Social Stress Test (TSST) and the Beilock Stress Test (BST) are two different stress protocols published in the literature. The present study has three objectives: 1) to compare the efficacy of two different previously documented psychological stressors, the TSST and the BST; 2) to compare an invasive measure, serum cortisol, to a non-invasive measure, the galvanic skin response (GSR); and 3) to examine the effects of sex on the response. Fifty-seven college age males (n = 31) and females (n = 26) completed both protocols. Blood samples were collected every 10 min for 110 minutes. Baseline, stressor, and recovery 1, 2, and 3 were averaged for a 20 min period. A 2 (test: BST or TSST) by 2 (sex: male or female) by 5 (trials: baseline, stressor, and recovery 1, 2, and 3) Mixed Plot ANCOVA with repeated measures on test and trial was used to analyze the data. There was not a significant main effect for test or sex for cortisol or the GSR. There was a significant difference for trial for both biomarkers: cortisol F(4,208) = 39.41; and GSR F(4,216) = 15.18. There was also a significant interaction term for sex × trial × test, F(4,208) = 4.51 and for test × trial, F(4,208) = 14.31 for cortisol. The conclusion is that the TSST and the BST can be used as pretest posttest stressors in translational studies assessing the effectiveness of a stress reduction technique if slight modifications are made in the statistical design.

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