BACKGROUND The African clawed frog, Xenopus laevis, is widely used in studies of oogenesis, meiotic cell cycle and early embryonic development. However, in order to perform such studies, eggs are normally collected after the injection of hCG into the dorsal lymph sac of fully-grown female frogs following pre-injection of PMSF. Although this protocol is established and used as standard laborator...

Use of GnRH in AI protocols results in ovulation of a wide range of follicle sizes. Our objective was to determine the effect of ovulatory follicle size at GnRH-induced ovulation or standing estrus on pregnancy rates and embryonic/fetal mortality. Lactating beef cows (n = 273) received the CO-Synch protocol (100 μg GnRH, i.m. on d -9; 25 mg PG, i.m. on d -2; and 100 μg GnRH, i.m. on d 0 with ti...

Ovulation in camelids is induced by an unidentified protein in the seminal plasma of the male termed 'ovulation-inducing factor'. This protein has been reported to be a 14-kDa protein under reducing conditions, which, when purified from seminal plasma, induces ovulation in llamas. The identification of this protein and investigation of its potential to induce ovulation in camelids may aid the d...

A cDNA for a prostaglandin E(2) (PGE(2)) receptor subtype 4, EP4b (Ptger4b), was cloned from the medaka ovary. The effect of PGE(2) was examined using COS-7 cells expressing the recombinant Ptger4b protein. An increase in intracellular cAMP levels was observed when the cells were incubated with PGE(2), but the increase in cAMP levels was nullified by the addition of the EP4 antagonist GW627368X...

OBJECTIVE To investigate the influence of substance P on gonadotropin release from the pituitary as evaluated according to the final effect, i.e. the ovulation. METHODS Stainless steel tube was implanted into the 3rd cerebral ventricle and substance P (SP), C-terminal hexapeptide of Substance P (SP6-11), Gn-RH and adrenaline were infused on the 3rd day of the cycle (proestrus). The oviducts w...

mone (LH). The increase in rats is preceded by increases in ovarian levels of cyclic AMP and progesterone. Systemic administration of indomethacin prevented the increase of ovarian prostaglandin F and blocked ovulation in rabbits and rats. Intrafollicular injection of indomethacin, in rabbits, at dosages which were ineffective when given via systemic injection, blocked the elevation of follicul...

Each month, many women experience an ovulatory cycle that regulates fertility. Although research has found that this cycle influences women's mating preferences, we proposed that it might also change women's political and religious views. Building on theory suggesting that political and religious orientation are linked to reproductive goals, we tested how fertility influenced women's politics, ...