THE BIOLOGY OF PUBERTY

The objective of this review was to develop a broader, more biological, overview of puberty, as opposed to the more limited, laboratory-dominated, view that has emanated from experimental physiology. Three conceptual schemes form the basis for our broader perspective. The first deals with the ways in which genes and environmental factors interact to program the timing of reproductive development. The second focuses on the ways environmental factors interact with each other to influence puberty. The third relates the genetic and environmental controls to specific endocrine and neuroendocrine pathways of action.
The more traditional approach of studying domesticated animals under carefully controlled conditions predetermines one's conclusions. One logically will conclude that the final stages of reproductive development are rather rigidly determined genetically and not greatly subject to environmental regulation, except for obviously adaptive pheromonal and photoperiodic regulation. One also will search within the reproductive axis itself for the final developmental step that allows functional fertility. In contrast, a more biological view suggests that for most mammals puberty is a highly labile process subject to several kinds of environmental influences that operate at many times during a mammal's life. Furthermore this perspective suggests that the final developmental step allowing fertility onset normally will occur outside rather than within the reproductive axis proper. This conclusion has a potentially great impact upon the way we look at the organization of the brain and endocrine system and in the way we choose animal models for studying human puberty and the types of controls we study.