[Several aspects of the problem of the development of hormonal regulation during prenatal development]

Some general aspects of the problem of hormonal control mechanisms in prenatal life are discussed. An analysis is performed on the basis of both the literary and author's data pertaining to the development of hypothalamo-hypophysial-adrenal, hypothalamo-hypophysial-thyroid and hypothalamo-hypophysial-gonadal functions during the foetal life. Experimental evidences of the activity of these functions in foetuses are provided. Neuroendocrine mechanisms are considered as a system of coordinated and intercontrolling links where the relative autonomy, the self-regulation of lower levels is coupled with the centralized control of higher levels. A concept is put forward to the effect that interactions between individual links play an important part in the formation of these mechanisms. If it is so, organizing influences, or stimuli, may emanate both from higher levels of control towards the lower ones and vice versa. Hormonal influences in early ontogenesis are characterized by the fact that, besides direct effects at the same developmental stage, they ensure the maturation of higher levels of neuroendocrine mechanisms which perform hormonal control in adults.