The effect of age on the female reproductive tract of the hopping-mouse Notomys alexis

Abstract

The effect of age on the female reproductive system of N. alexis was investigated in the following age groups: (1) 2.5-6 months; (2) 1-2 years; (3) >2 years old. Oestrous cycle length was slightly reduced in group 2 females relative to group 1, but most group 3 females showed either constant dioestrus or constant oestrus. Body, ovarian and uterine weights all tended to increase with age, and Graafian follicles and corpora lutea were present in females in all groups although the latter were significantly fewer in group 3. Cytology of uterine epithelial cells of females in dioestrus indicated that numbers of microvilli in old animals were somewhat variable but generally decreased, some cells appearing almost devoid of them, whereas numbers of secondary lysosomes and multi-vesicular bodies tended to increase. The effect of these differences on possible infertility have, however, yet to be proved.