[Peculiarities of ovarian and adrenal histophysiology in female rats producing the offspring with an accelerated brain development].

The purpose of the present study was to determine what peculiarities of endocrine and reproductive systems of female rats may favor the birth of the offspring with an accelerated brain development. The study included 20 female rats examined 1 day after the parturition and their 1-day-old offspring (n = 201). In females the activity of 3b-hydroxysteroid dehydrogenase (HSD) and lipid concentration were determined in ovarian steroid-producing structures and in all the zones of adrenal cortex. Estradiol and triiodothyronine concentrations were measured in blood and the prenatal mortality of the offspring was determined. In newborn rats the brain mass, neocortex and its layer I thickness were measured as well as the numerical density of neurons in layer V. Using the method of cluster analysis, newborn rats and their mothers were divided into 3 groups, depending upon the degree of brain development of the offspring. It was shown that an accelerated brain development was associated with somewhat smaller number of newborn rats per litter, an increased prenatal fetal loss, and lower HSD activity in ovarian and adrenal cortex steroid-producing cells, low estradiol concentration in blood. It is assumed that these peculiarities of maternal endocrine and reproductive systems could cause a higher level of brain development in their offspring.

[Comparisons of brain weight and neocortical thickness in 21-day-old fetuses and 1-day-old rats with the histophysiological indices of the ovaries and adrenal glands of their mothers (a correlational and cluster analysis)]. / Sopostavleniia massy golovnogo mozga, tolshchiny neokorteksa u 21-dnevnykh plodov i 1-dnevnykh krys s pokazateliami gistofiziologii iaichnikov i nadpochechnikov ikh materei (korreliatsionnyi i klasternyi analiz).

The correlation and cluster analysis revealed that the brain weight of the rat 21-day-old foetus obviously depended on 3 beta-hydroxysteroiddehydrogenase activity in adrenal cortex. No such dependence was found in 1-day-old foetus. Thickness of the brain cortex in 21-day-old foetus and in 1-day-old rat correlated with parameters of the enzyme activity in the corpus luteum, corpus atretic, and theca folliculi of mother's ovaries.