Differences in gonadotrophin-stimulated cyclic AMP production by granulosa cells from booroola x merino ewes which were homozygous, heterozygous or non-carriers of a fecundity gene influencing their ovulation rate.
Granulosa cells from follicles of different sizes from Booroola x Merino ewes which were homozygous (FF), heterozygous (F+) or non-carriers(++) of a fecundity gene were obtained 0-48 h after cloprostenol injection on Day 10 of the oestrous cycle. The highest mean amounts of cAMP produced by the cells did not differ between the genotypes. However, in the ++ ewes it was attained by cells from follicles greater than or equal to 5 mm in diameter, whereas in F+ and FF ewes it was attained by cells from follicles 3-4.5 mm in diameter. Cells from 1-2.5-mm diameter follicles of FF ewes were more sensitive to FSH and LH than were corresponding cells from F+ or ++ ewes. Granulosa cells from greater than or equal to 5 mm diameter follicles of ++ ewes 12-24 h after injection of cloprostenol had a lower mean response to FSH and LH than did cells obtained 0-6 or 36-48 h after cloprostenol. No such effect of time was evident for cells from any size of follicles obtained from F+ or FF ewes. In 1-2.5-mm diameter follicles, the mean aromatase activity of granulosa cells from ++ and F+ ewes was similar, but significantly lower than that of cells from FF ewes. In 3-4.5 mm diameter follicles, the mean aromatase activity of cells from F+ and FF ewes was similar, and significantly higher than that of cells from ++ ewes. For all 3 genotypes, there was a significant positive relationship between FSH or LH stimulation of granulosa cell cAMP production and cellular aromatase activity.
Henderson
K M
KM
Wallaceville Animal Research Centre, Ministry of Agriculture and Fisheries, Upper Hutt, New Zealand.
McNatty
K P
KP
O'Keeffe
L E
LE
Lun
S
S
Heath
D A
DA
Prisk
M D
MD
D000818:Animals; D003008:Cloprostenol / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D005260:Female; D005298:Fertility; D005796:Genes; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D006579:Heterozygote; D006720:Homozygote; D006080:Ovarian Follicle / Q000033:anatomy & histology; D010060:Ovulation; D012756:Sheep
D003008:Cloprostenol; D000242:Cyclic AMP