title: Relationship of oestrogen and progesterone and their oviductal receptors in laying and non-laying 5-year-old hens.
abstract: This study focuses on the relationship of ageing to reproductive function in the domestic hen. Reproductive function was assessed by egg-laying records of hens from the same flock of 4, 5 and 6 years of age. Egg laying decreased with advancing age and the percentage of non-laying hens increased. During an ovulatory cycle, plasma levels of oestrogen and progesterone (including the preovulatory surge) were similar in both the 5-year-old and 1-year-old laying hens. In both young and old non-laying hens, the preovulatory surge of progesterone was absent. Levels of oestrogen were similar for all hens, but the oestrogen-dependent oviduct was atrophied in non-laying 5-year-old hens. This reduction in oviductal size was correlated with reduced levels of magnal nuclear oestrogen receptor and cytosol progesterone receptor. These results suggest a refractoriness of the oviduct to oestrogen stimulation in the ageing hen.
mesh_terms: D000375:Aging; D000818:Animals; D002645:Chickens / Q000502:physiology*; D004967:Estrogens / Q000097:blood*; D005260:Female; D010057:Oviducts / Q000032:analysis / Q000033:anatomy & histology / Q000502:physiology*; D010058:Oviposition; D010060:Ovulation; D011374:Progesterone / Q000097:blood*; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D011374:Progesterone