The neonatal testosterone surge: A comparative study

Abstract

In the rat an abrupt discharge of testicular testosterone in the newborn male figures prominently in the development of mechanisms controlling gonadotropin secretion, sexual behavior, and also promotes the functional differentiation of the accessory sex glands. In this study we detail the temporal characteristics of this surge in the rat, and we provide comparative data documenting a similar surge-like appearance of testosterone in neonatal male mice, recently foaled male horses, and newborn human infants. Although the physiological and behavioral significance of this phenomenon for species other than the rat remains to be determined, the apparently ubiquitous appearance of the neonatal testosterone surge suggests that it may be of special significance in the sexual differentiation of many mammalian species.

Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder

“…Thus, lower amplitude CEOAEs, present in males, are proposed to originate from high prenatal exposure to androgens, which are suggested to diminish emission strength (McFadden, 1993(McFadden, , 1998McFadden et al,1996). The dampening effects of androgens on CEOAEs may not be restricted to the prenatal period, but rather extend to and coincide with the peri-/ postnatal testosterone surge in male infants (Corbier, Edwards, & Roffi, 1992;Quigley, 2002). For instance, testosterone levels in male infants, assessed between the first 6 months post-natally, have recently been associated with later sex-typed play behavior in children (Lamminmäki et al, 2012).…”

17β-Estradiol protects the neonatal brain from hypoxia–ischemia

“…By the end of the first postnatal week in rats (when H/I was administered), estradiol levels are naturally waning (Dohler and Wuttke, 1974;Weisz and Ward, 1980). Similarly, following birth, estradiol levels in humans are dropping (Forest, 1979;Corbier et al, 1992). Therefore, the treatment regiment used in the present study may be applicable not only to other animal models of postnatal brain injury, but may also be appropriate for human infants at risk for traumatic events such as H/I.…”

“…testosterone, estradiol, and progesterone) are elevated, comparable to levels in adulthood (Warne et al, 1977;Forest, 1979;Weisz and Ward, 1980;Corbier et al, 1992;Knickmeyer and Baron-Cohen, 2006). Levels of testosterone and estradiol are elevated from embryonic day 17 though embryonic day 21 in rats, with another surge in hormone levels occurring immediately after birth.…”

“…Levels of testosterone and estradiol are elevated from embryonic day 17 though embryonic day 21 in rats, with another surge in hormone levels occurring immediately after birth. Elevated levels persist through the first postnatal week of life in rats (Dohler and Wuttke, 1974;Forest, 1979;Weisz and Ward, 1980;Corbier et al, 1992). In humans, testosterone biosynthesis begins around gestational week 9, with elevated levels of both testosterone and estradiol (due to aromatization from testosterone) persisting through gestational week 24 (Warne et al, 1977;Knickmeyer and Baron-Cohen, 2006).…”

“…Progesterone levels in rats and humans are elevated prior to birth, dropping precipitously at birth (Warne et al, 1977;Forest, 1979). Testosterone and 17β-estradiol levels are relatively equivalent between immature rats and humans (Forest, 1979;Corbier et al, 1992), however sex differences exist in testosterone production (males>females) (Warne et al, 1977;Forest, 1979;Corbier et al, 1992;Knickmeyer and Baron-Cohen, 2006). The developmental production of steroid hormones (i.e.…”