Prepubertal ontogeny of responsiveness to estradiol in female rat central nervous system

The physiological response to systemic estrogens changes dramatically during the period from birth to puberty. With the onset of puberty, the rat reaches a critical developmental plateau with regard to endocrinological responsiveness to estradiol. Since the appearance of the pubertal response pattern appears to be less a consequence of some intrinsic "trigger' than the natural continuation of a developmental sequence that begins prenatally, its ontogeny should be examined in a broad context that will take account of the impact of each of the dynamic components influencing the interactions between estradiol and the central nervous system on the functional development of the organism as a whole. The prepubertal ontogeny of endocrinological responsiveness to estradiol in the central nervous system of the female rat is examined in the context of several of the important factors that are known to influence the functional development of the hypothalamo-pituitary-gonadal circuit:the rapidly changing hormonal environment of the morphologically and physiologically immature juvenile rat, the shifting predominance of alphafetoprotein and "adult" estradiol-binding protein, sexual differentiation of the neural substrate, and the development of mature pituitary-gonadal feedback mechanisms. The availability of ever more sensitive techniques for the measurement of the actions of estradiol in the central nervous system of the immature organism has necessitated a re-evaluation of existing data. This, in turn, suggests that new approaches should be applied to the examination of problems related to the development of reproductive maturity of the central nervous system.