Pubertal maturation inside the skin: Sex-specific changes in gonadal hormones in saliva and hair

• In Event: 3-212 - Toward Multisystemic Models of Pubertal Timing and Tempo

Integrative Statement

Puberty is a developmental period marked by the activation of the hypothalamic-pituitary-gonadal (HPG) axis, resulting in increases in gonadal hormones such as testosterone and estradiol (Cameron, 2006). Increases in these sex steroids catalyze the sex-specific development of secondary sex characteristics and reproductive maturation. The rapidness of puberty, or tempo, is often assessed by self- or physician-reports of the development of these secondary sex characteristics (Mendle, Harden, Brooks-Gunn, & Graber, 2010). However, the rapid rise in hormones during puberty may capture pubertal tempo inside the skin. Though testosterone is primarily responsible for reproductive maturation in males, and estradiol, in females, both gonadal hormones rise in both sexes (Cameron, 2006). The current study examined whether hormones measured from saliva and hair across two time points reflect puberty-specific sex differentiated maturation over time.

Participants for the current study are a subsample of children and adolescents from the Texas Twin Project (Harden, Tucker-Drob, & Tackett, 2012), a population representative sample from central Texas, with two time points of hormone sample collection. Salivary hormones were collected for a subsample of adolescents (13.6 – 19 years), with 143 participants providing usable testosterone measurements (52% female) and 141 with usable estradiol (54% female). The average time between waves was approximately 2.5 years. Testosterone was assayed in hair from a larger age range (7.8 – 19 years), with 294 participants providing usable testosterone measurements (59% female) with an average of 1.25 years between waves. Estradiol measurement in hair was not available due to estradiol concentrations below the detectable limit in hair. Race, BMI, and analytic batch were controlled for in all hormones, as well as time since waking for salivary hormones. Hormone concentrations were log transformed and windorized. The Pubertal Development Scale (PDS) was used to assess self-reported pubertal maturation for all participants at both time points (Petersen, Crockett, Richards, & Boxer 1988).

Multilevel longitudinal models assessed the linear, quadratic and cubic effects of PDS controlling for age, and included sex interactions to account for sex differences. Log-likelihood, AIC, and BIC values were used for nested model comparisons. For both salivary testosterone and estradiol, the model with quadratic effects of PDS provided the best fit to the data (Δχ2 = 8.9 (2), p = 0.01; Δχ2 = 7.05 (2), p = 0.02 respectively, compared to the linear model), indicating and inverted U-shaped relationship between pubertal development and both gonadal hormones. Hormonal rise at the onset of puberty was greater in females than males for both testosterone and estradiol. Change in salivary hormones over pubertal development by sex is depicted in Figure 1, with estimates provided in Table 1. For hair testosterone, the linear model provided the best fit but no significant effects were detected (Table 1). These results provide preliminary evidence that intraindividual change in salivary hormones may be used as a proximal measure of progression through puberty. That similar effects were not found for hair testosterone may indicate that the chronic accumulations of hormones detected in hair are inadequate to capture rapid changes during puberty.

Authors

• Megan Patterson, University of Texas at Austin
  Presenting Author

• Andrew Grotzinger, University of Texas at Austin
  Non-Presenting Author

• James Madole, University of Texas at Austin
  Non-Presenting Author

• Elliot M. Tucker-Drob, University of Texas at Austin
  Non-Presenting Author

• Kathryn Paige Harden, University of Texas at Austin
  Non-Presenting Author