A seasonal difference in ovine peripheral plasma prolactin and progesterone concentrations in early pregnancy and in the relationship between the two hormones.

摘要: Behavioural oestrus and ovulation in the sheep can be induced during seasonal anoestrum by means of exogenous hormones, but fertility is lower than ewes treated similarly natural breeding season (Allen & Lamming, 1960; Robinson, 1971). Whether or not caused differences endocrine status ewe early pregnancy has been resolved. Differences peripheral plasma progesterone concentrations mated December March have reported (Rhind, Fraser Phillippo, 1977) these were attributable to rate, nutrition because diet feeding regimens same for each time year. Although there evidence that prolactin luteotrophic (Denamur, Martinet Short, 1973), studies luteinized human granulosa cells vitro indicate while low are required production, high an inhibitory effect (McNatty, Sawers McNeilly, 1974). We therefore investigated concentration at two times year relationship between concentrations.