Interrelationship between the ovary & thyroid during the estrous cycle of rats

The present inve’stigation was done to swdy the changes ef thyroxine (T4) and triiodot’hyronine (T3) ,in diffe’rent pha.s e s of estrous cycle in mature albino rats with especial references to the synthesis and release of TSH. Also we study the effects of anties- tradiol .an d antipr~ge,strone sera on the responsiveness (l)f thyroid and ,pi~U:~ tary durinThis study Lnc Lude s 2 experiment s:In the first experiment, eightyfour mature femafe albino rats of a regular’ c,yclic 5 day pattern were selected andh), proestrus (1600’h), early estrus (0900 h DI), late estrus (0900 h D2) Metestrus(M:0900 h) early diestrus(0900 h DI) and ~ate ~iestrus (0900 h D2).All rats wer”e decapitated and serum samples were collected separately. The pitulteries and thyroids of rats were dissected and weighed. Pituiteries were ster- ed separately in’ aceten~ and kept in deep fre-eze (_20°C) The thyroids were fixed in neutral f