FSH and LH receptor concentrations in large ovarian follicles of beef cows in high and low levels of body condition at nine weeks post partum.
An experiment was conducted to determine whether or not the effect of body condition at parturition, and thereafter, on the duration of the post-partum anoestrous period was mediated through differences in gonadotrophin receptor concentrations in the ovarian follicles. Two groups of cows were fed to achieve body condition scores of > or = 2.75 (H; n = 14) or < or = 2.00 (L; n = 15) at parturition (this had led to differences in the duration of post-partum anoestrus in previous experiments) and then fed to maintain liveweight and condition until ovariectomy at nine weeks post partum. There was no effect of body condition on the mean (+/- s.e.) number of large (> or = 8 mm diameter) follicles per cow (3.0 +/- 0.27) but a greater proportion of the follicles of H cows, compared with L cows, was oestrogenic (secreting > 250 pg oestradiol h-1 in culture) (0.75 v. 0.5; chi 2 = 3.40; P = 0.06). Mean concentrations (pg hormone bound per mg protein) of follicle stimulating hormone (FSH) receptors in both granulosa (H, 157.3; L, 136.6; standard error of difference (s.e.d.) = 27.2) and thecal tissue (H, 4.14; L, 4.35; s.e.d. = 1.66) were similar for H and L cows. There was no difference associated with treatment in luteinizing hormone (LH) receptor concentrations in either granulosa (H, 40.3; L, 37.2; s.e.d. = 6.67) or thecal tissue (H, 48.9; L, 48.0; s.e.d. = 6.03). The concentration of FSH receptors in granulosa tissue was lower in non-oestrogenic follicles than in oestrogenic follicles (80.0 v. 188.1; s.e.d. = 40.4; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Rhind
S M
SM
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, Scotland.
Bramley
T A
TA
Wright
I A
IA
McMillen
S R
SR
D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000502:physiology*; D004958:Estradiol / Q000032:analysis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D015571:Follicular Fluid / Q000737:chemistry; D006107:Granulosa Cells / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D009752:Nutritional Status / Q000502:physiology; D006080:Ovarian Follicle / Q000378:metabolism*; D049590:Postpartum Period / Q000378:metabolism*; D011897:Random Allocation; D011962:Receptors, FSH / Q000096:biosynthesis*; D011974:Receptors, LH / Q000096:biosynthesis*; D013739:Testosterone / Q000032:analysis; D013799:Theca Cells / Q000378:metabolism
D011962:Receptors, FSH; D011974:Receptors, LH; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone