POTENTIAL FERTILITY, EMBRYONIC-DEVELOPMEN T, AND HORMONAL STATUS OF RATS SELECTED FOR REACTION OF ESTROUS-CYCLE TO PERMANENT ILLUMINATION

Illumination responsiveness (IR) is studied by selection experiments w ith outbred Wistar rats. Under selection is oestral cyclics under perm anent illumination (PI) condition, changes in hormonal status, potenti al fertility, and embryonic developments ats different stages are regi stered and compared with control. Results indicate significant changes in endocrine regulatory system in the lines exposed to PI. Functional potentiality of reproductive system gets more weak as a result of thi s selection, which leads to decreasing in number of ovulations, defect ive development of placenta, less embryo weights, higher embryo mortal ity. The opposite conditions are observed in rats undergone selection of stability of oestral cycle. It is concluded that the above selectio n reveals formation of regulatory mechanisms of reproduction on differ ent genetical physiological bases.