The effect of intrauterine progesterone treatment on the endometrial prostaglandin F content in the rabbit

Hormonal contraceptives, stress, and the brain: The critical need for animal models

Hormonal contraceptives are among the most important health and economic developments in the 20thCentury, providing unprecedented reproductive control and a range of health benefits including decreased premenstrual symptoms and protections against various cancers. Hormonal contraceptives modulate neural function and stress responsivity. These changes are usually innocuous or even beneficial, including their effects onmood. However, in approximately 4-10% of users, or up to 30 million people at any given time, hormonal contraceptives trigger depression or anxiety symptoms. How hormonal contraceptives contribute to these responses and who is at risk for adverse outcomes remain unknown. In this paper, we discussstudies of hormonal contraceptive use in humans and describe the ways in which laboratory animal models of contraceptive hormone exposure will be an essential tool for expanding findings to understand the precise mechanisms by which hormonal contraceptives influence the brain, stress responses, and depression risk.

Contribution to the pathogenesis of dysmenorrhea

Menstrual blood was collected from five eumenorrheic and seven dysmenorrheic women aged between 20 and 35 years for a period of three cycles each. The levels of prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), 6-keto-prostaglandin F1 alpha (6-k-PGF1 alpha)-the stable metabolite of prostacyclin (PGI2)-, oestradiol, oestrone, and progesterone were determined radioimmunologically. Both eumenorrheic and dysmenorrheic women showed identical blood losses. The levels of oestradiol excreted by the dysmenorrheic women were markedly elevated as compared to the non-dysmenorrheic subjects (2 p less than 0.05). Oestrone excretion was in the same order of magnitude in all subjects examined. The concentration of progesterone per menstruation was significantly higher in the eumenorrheic women (2 p less than 0.02) than in the dysmenorrheic patients. Menstrual excretion of PGF2 alpha was 2.5 times higher in the dysmenorrheic women compared to the normal subjects (2 p less than 0.05). The levels of PGE2 was identical in both groups. Excretion of 6-k-PGF1 alpha was significantly lower in the dysmenorrheic women than in the eumenorrheic subjects (2 p less than 0.02). The oestradiol/progesterone ratio showed a distinct predominance of oestradiol in the dysmenorrheic patients. PGF2 alpha dominance in the dysmenorrheic patients is expressed by the PGF2 alpha/6-k-PGF1 alpha and the PGF2 alpha/PGE2 ratios. A shift in the oestradiol/progesterone ratio in favour of oestradiol seems to be the underlying pathogenic principle of dysmenorrhea. The oestradiol dominance is associated with a shift in the PGF2 alpha/PGI2 and the PGF2 alpha/PGE2 proportions. Thus, the PGF2 alpha predominance and a simultaneous reduction of PGI2 in uterine tissue seem to be responsible for dysmenorrheic bleeding.

Control of endometrial prostaglandin output in vitro during the estrous cycle of the guinea-pig: influence of estradiol 17-beta, progesterone, oxytocin and calcium ionophore A23187

Agents influencing the output of prostaglandin F2 alpha (PGF2 alpha) from non-pregnant endometrium were investigated by in vitro incubation, for 5 and 19h, using mid-cycle (day 7), end of cycle (day 15), or ovariectomised guinea-pigs. Estradiol 17-beta (10 micrograms/ml) stimulated PGF2 alpha output 24h after incubation with endometrium (p less than 0.05). This stimulation was greater at mid-cycle. Progesterone (50 ng/ml) inhibited output of PGF2 alpha (p less than 0.05) in mid-cycle, end of cycle and ovariectomised guinea-pig cultures. Oxytocin (1 X 10(-5) u/ml) stimulated the output of PGF2 alpha at the end of the cycle, but not at mid-cycle. However, in the presence of estradiol 17-beta (10 micrograms/ml), oxytocin stimulation of mid-cycle PGF2 alpha output was observed. The calcium ionophore A23187 (5 micrograms/ml) stimulated PGF2 alpha synthesis from mid-cycle and end-of-cycle endometrium, and this stimulation resembled that caused by arachidonic acid (100 micrograms/ml), suggesting an action via substrate mobilisation. Co-culture of endometrium and myometrium did not influence endometrial PGF2 alpha or myometrial 6-oxo-PGF2 output. It is suggested that the steroid hormones act as coarse modulators of endometrial PGF2 alpha output, but more rapid changes may be achieved by oxytocin and agents that mobilise substrate supply, possibly via calcium ion fluctuations.

The effect of a progesterone-releasing intrauterine contraceptive device on uterine secretion of prostaglandin F2alpha and life-span of corpora lutea in the ewe

Two studies were conducted to investigate the effect of a progesterone-releasing intrauterine contraceptive device (IUD) on uterine secretion of prostaglandin (PG) F2alpha associated with IUD-induced luteolysis in sheep. In bilaterally ovulating ewes receiving an IUD on day 3 (estrus = day 0) intrauterine release of progesterone (90 microgram per day) by the device did not prevent premature luteolysis or the increased concentration of PGF2alpha in uterine venous plasma on day 5 caused by conventional IUD's. In the second study a progesterone-releasing IUD (645 microgram per day) inserted adjacent to the intact ovary at unilateral ovariectomy on day 14 inhibited early luteolysis in the subsequent estrous cycle and reduced the uterine secretion of PGF2alpha on day 5, without affecting concentrations of progesterone in the peripheral circulation at the intervening estrus. It is suggested that locally delivered intrauterine progesterone can inhibit IUD-induced luteolysis in the ewe by suppressing the uterine secretion of PGF2alpha.

Effect of sparteine sulfate on uterine prostaglandin F in the rat

Indomethacin, an inhibitor of prostaglandin synthetase, added to an in vitro bath in a concentration of 1, 5, and 10 X 10(-6) g/ml reduced sparteine-induced contractions of isolated uterine segments from pregnant rats. Contractions induced by prostaglandin F2alpha and acetylcholine were not reduced. Sparteine increased the prostaglandin F content of the blood and uterine tissue in the pregnant but not in the nonpregnant rat. This increase was significantly reduced by the administration of indomethacin (10 mg/kg). The present study suggests that the mechanism of sparteine action is mediated through a prostaglandin F system.

Endometrial prostaglandin F content in women wearing nonmedicated or progestin-releasing intrauterine devices

Prostaglandin F (PGF) was measured in endometrial samples from eight women wearing Lippes Loops and 14 women wearing Progestaserts after 6 months' use of the intrauterine devices (IUDs). In addition, in 37 women wearing dydrogesterone-T IUDs, endometrial PGF was measured after 1 month, 3 to 7 months, and 8 to 12 months of use. Endometrial samples were also obtained from 51 women without IUDs. The following means and standard errors of endometrial PGF, expressed in picograms per microgram of endometrial protein, were obtained in women without IUDs: early proliferative phase, 3.11 +/- 1.0; midproliferative phase, 4.1 +/- 0.7; late proliferative phase, 4.4 +/- 1.0; midluteal phase, 7.13 +/- 1.0; and late secretory phase, 6.08 +/- 1.0. The midproliferative phase mean was significantly different from the midsecretory phase mean (P is greater than 0.05). Except for one group, no differences were noted during the midproliferative and midsecretory phases among the groups of women wearing medicated and nonmedicated IUDs, when compared with values for women without IUDs. The only difference noted was during the midsecretory phase in the dydrogesterone group at 8 to 12 months. In these women, the mean endometrial PGF content was 2.8 +/- 0.8, significantly different (P is greater than 0.05) from that of women without IUDs (6.1 +/- 1.0).