Diurnal and seasonal rhythms of cortisol, testosterone, and DHEA were examined, as little is known about the relationship between these rhythmicities and pubertal development. Salivary samples were obtained from 60 boys and 60 girls at approximately 07:45, 08:00, 08:30, 12:00, 16:50, and 21:00 h. The participants' ages ranged from 8-14 yrs, and each participant was tested three times at six-month intervals. The study was conducted at a General Clinical Research Center (GCRC) and at the homes of the participants. All hormones showed diurnal fluctuations. The acrophase (peak time) of cortisol occurred earlier than for testosterone or DHEA and showed a seasonal effect, with the acrophase occurring earlier in spring than in summer. The cortisol acrophase also occurred later in the day for boys than for girls during later puberty. Seasonal effects were found only for cortisol with higher concentrations in the spring and summer. Cortisol concentrations were relatively stable across pubertal maturation, but significantly lower concentrations were observed at pubertal stage 3 compared to the other stages. Morning cortisol levels were also higher in boys at pubertal stage 2. Testosterone concentrations were higher in boys at pubertal stages 3 and 4, and DHEA was lower at pubertal stage 1 than 3 and 4 for both boys and girls. For the total sample, there was a positive correlation between DHEA and testosterone during early puberty (stages 1-3) but not later puberty (stages 4-5). Awakening secretory activity correlated with daytime secretory activity for testosterone and DHEA, but not for cortisol. These data provide novel chronobiological information on cortisol, testosterone, and DHEA as it relates to sexual maturation and encourage further study on both normal and abnormal endocrine rhythms.

Limited research has addressed how social support in the form of a pet can affect both sympathetic and hypothalamic-pituitary-adrenal reactivity in response to a psychological challenge. The present study examined the effects of social support on salivary cortisol and heart rate (HR). Forty-eight participants were randomly assigned to three different conditions (human friend, novel dog, or control). All participants completed the Trier Social Stress Test and provided cortisol, HR, and State-Trait Anxiety Inventory measures. For participants paired with a dog, overall cortisol levels were attenuated throughout the experimental procedure, and HR was attenuated during the Trier Social Stress Test. For all groups, state anxiety increased after the Trier Social Stress Test, and HR during the Trier Social Stress Test was a predictor of cortisol. These results suggest that short-term exposure to a novel dog in an unfamiliar setting can be beneficial. They also suggest a possible mechanism for the beneficial effect associated with affiliation with pets.

Family composition (e.g., the absence of a father) is associated with pubertal timing in women, although the socioendocrinology of the human primate is poorly understood. To better understand social influences on sexual maturation, retrospective data were collected on menarcheal age and family composition from a sample of approximately 1,938 participants from a college population. Absence of a biological father, the presence of half- and step-brothers, and living in an urban environment were associated with earlier menarche. The presence of sisters in the household while growing up, especially older sisters, was associated with delayed menarche. Menarcheal age was not affected by number of brothers in the household, nor was there an effect of birth order. Body weight and race were also associated with menarche. The present findings advance the literature as they are suggestive of putative human pheromones that modulate sexual maturation to promote gene survival and prevent inbreeding, as occurs in rodents and nonhuman primates.