Luteal characteristics and progesterone production on day 5 of the bovine oestrous cycle.
In this study we have examined luteal function in non-lactating and late lactation dairy cows on day 5 of the cycle, during the period of the post-ovulatory progesterone rise. Comparison of luteal progesterone content and in vitro synthetic capacity with circulating plasma progesterone demonstrated that circulating progesterone concentration is a function of total luteal activity rather than the activity of individual units of tissue. Incubation of luteal tissue in vitro demonstrated stimulatory activity of LH and IGF-I, and to a greater degree IGF-II, on luteal progesterone synthesis. Finally the study showed no effect of double ovulation on luteal function. Occurrence of double ovulation in 35% of animals was not associated with any difference in luteal function or plasma progesterone concentrations.
Green
M P
MP
Division of Animal Physiology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
Mann
G E
GE
Hunter
M G
MG
D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D030762:Estrous Cycle / Q000097:blood / Q000502:physiology*; D004971:Estrus / Q000097:blood / Q000502:physiology*; D005260:Female; D007774:Lactation / Q000502:physiology; D008184:Luteal Cells / Q000166:cytology / Q000502:physiology; D010060:Ovulation / Q000097:blood / Q000502:physiology*; D011374:Progesterone / Q000097:blood*; D011863:Radioimmunoassay / Q000662:veterinary
D011374:Progesterone