Regulation of ovarian hyperluteinization

Adult female rats with neonatally damaged posterior hypothalamus, made by a transversal cut, were investigated. Plasma levels of prolactin (PRL), gonadotropic hormones (GTH) and female gonadal steroids (GS) were determined by radioimmunoassay. The animals were sacrificed, at the ages of 4 and 6 months and their hypothalamus, pituitary gland, ovary and uterus were examined using light microscopy. The results can be summarized as follows: body mass of animals, with damaged posterior hypothalamus, was significantly reduced. Masses of luteinized ovaries were increased and uterine tissues decreased. Serum levels of PRL were significantly increased and luteinizing hormone (LH) decreased. Ultrastructural changes in the corpora lutea (CL), previously described, showed clear signs of their reduced capacities to produce GS, both estradiol (Oe) and progesterone (Pg) per total ovarian mass. However, prostaglandin 2 alfa (PGF2alpha) known as a luteolytic factor, was also diminished in the evidently retarded endometrium. As a result of decreased plasma values of LH, Pg and PGF2 alpha, luteolysis of CL in hyperluteinized ovaries did not occur, and their new generations were accumulated during subsequent cycles. The character of interruption and recovery of aminergic and peptidergic neurons, involved in regulation of hypothalamic-pituitary gonadal axis and feed-back effects of steroid hormones, require further studies.