PITUITARY LH CONTENT AND REPRODUCTIVE TRACT CHANGES DURING THE MOUSE OESTROUS CYCLE

Abstract

Summary. Body, uterine, ovarian and pituitary weights, and pituitary lh content were determined on each day of the oestrous cycle of individually housed, spontaneously cyclic mice. Uterine and pituitary weights varied significantly; uterine weight was maximum at pro-oestrus and pituitary weight was maximum at oestrus. The cyclic changes in the vaginal smear cells were correlated with the cyclic ovarian changes; the morning of di-oestrus I (2 mornings after newly ovulated ova are found in the oviduct) was the most useful marker for cycle stage, since it could always be recognized as the 1st morning on which only leucocytes and nucleated epithelial cells (no cornified cells) were present in the vaginal smear. In additional studies, females, which had been previously grouped (ten/cage), were paired individually with males and killed on days of 'induced' pro-oestrus (pre-ovulatory) or oestrus (post-ovulatory). The organ weights and pituitary lh content of these mice did not differ significantly from those obtained for spontaneously cyclic mice on the corresponding 2 days of the cycle.