During pregnancy, 64-96% of women take at least one prescription drug. The placenta is the primary barrier between substrates in maternal and fetal circulation. The blood-brain barrier (BBB) acts as an additional barrier for the fetal brain, which is particularly susceptible to the effects of xenobiotics. Multidrug resistance phosphoglycoprotein (P-gp; encoded by Abcb1 mRNA) and breast cancer resistance protein (Bcrp1; encoded by Abcg2 mRNA) are efflux transporters localized on placental syncytiotrophoblast and capillary endothelial cells of the BBB. Placental Abcb1/P-gp and Abcg2/Bcrp1 limit maternal-fetal transfer of endogenous and exogenous substrates. Similarly, the neuroprotective roles of Abcb1/P-gp and Abcg2/Bcrp1 in the adult BBB have been demonstrated. However, developmental changes in expression and function and regulation of Abcb1/P-gp and Abcg2/Bcrp1 in these tissues are poorly understood. This thesis investigates gestational changes in expression and function of Abcb1/P-gp and Abcg2/Bcrp1 in the placenta and fetal brain, in addition to regulation by steroids, progesterone and glucocorticoids. The effects of glucocorticoids on Abcb1/P-gp and Abcg2/Bcrp1 in the placenta and fetal brain are of importance given that 10% of pregnant women are treated with synthetic glucocorticoids during the management of threatened preterm labour. These studies demonstrate that the decrease in placental Abcb1/P-gp mediated fetal protection near term is compensated by an increase in Abcb1/P-gp and Abcg2/Bcrp1 mediated neuroprotection in the fetal brain; likely in preparation for life ex-utero. The lack of effects of progesterone and the dose-, age- and sex- dependent regulatory effects of synthetic glucocorticoid have highlighted the complexity associated with regulation of these transporters. Further, these studies are the first to report sexually dimorphic glucocorticoid effects on Abcb1/P-gp and Abcg2/Bcrp1 expression and function, with the female fetus being particularly susceptible to glucocorticoid these effects. In this regard, Abcb1/P-gp and Abcg2/Bcrp1 transport capacity may be altered when synthetic glucocorticoid is administered as a co-therapy, and as such, recipient sex should be considered during pharmacotherapy. Understanding the regulation of Abcb1/P-gp and Abcg2/Bcrp1 expression and function in the placenta and fetal brain during normal development and under pathological conditions is critical for fetal health and development, particularly when therapeutic strategies are utilized in pregnancy.

During pregnancy, 64-96% of women take at least one prescription drug. The placenta is the primary barrier between substrates in maternal and fetal circulation. The blood-brain barrier (BBB) acts as an additional barrier for the fetal brain, which is particularly susceptible to the effects of xenobiotics. Multidrug resistance phosphoglycoprotein (P-gp; encoded by Abcb1 mRNA) and breast cancer resistance protein (Bcrp1; encoded by Abcg2 mRNA) are efflux transporters localized on placental syncytiotrophoblast and capillary endothelial cells of the BBB. Placental Abcb1/P-gp and Abcg2/Bcrp1 limit maternal-fetal transfer of endogenous and exogenous substrates. Similarly, the neuroprotective roles of Abcb1/P-gp and Abcg2/Bcrp1 in the adult BBB have been demonstrated. However, developmental changes in expression and function and regulation of Abcb1/P-gp and Abcg2/Bcrp1 in these tissues are poorly understood. This thesis investigates gestational changes in expression and function of Abcb1/P-gp and Abcg2/Bcrp1 in the placenta and fetal brain, in addition to regulation by steroids, progesterone and glucocorticoids. The effects of glucocorticoids on Abcb1/P-gp and Abcg2/Bcrp1 in the placenta and fetal brain are of importance given that 10% of pregnant women are treated with synthetic glucocorticoids during the management of threatened preterm labour. These studies demonstrate that the decrease in placental Abcb1/P-gp mediated fetal protection near term is compensated by an increase in Abcb1/P-gp and Abcg2/Bcrp1 mediated neuroprotection in the fetal brain; likely in preparation for life ex-utero. The lack of effects of progesterone and the dose-, age- and sex- dependent regulatory effects of synthetic glucocorticoid have highlighted the complexity associated with regulation of these transporters. Further, these studies are the first to report sexually dimorphic glucocorticoid effects on Abcb1/P-gp and Abcg2/Bcrp1 expression and function, with the female fetus being particularly susceptible to glucocorticoid these effects. In this regard, Abcb1/P-gp and Abcg2/Bcrp1 transport capacity may be altered when synthetic glucocorticoid is administered as a co-therapy, and as such, recipient sex should be considered during pharmacotherapy. Understanding the regulation of Abcb1/P-gp and Abcg2/Bcrp1 expression and function in the placenta and fetal brain during normal development and under pathological conditions is critical for fetal health and development, particularly when therapeutic strategies are utilized in pregnancy.

The objective was to investigate the effects of progesterone (P4) on luteinizing hormone (LH) release, follicle development, and oocyte competence in cattle. We tested the general hypotheses that: 1) The suppressive effect of P4 on gonadotrophin releasing hormone (GnRH)-mediated LH release can be overcome by increasing GnRH dose or pre-treatment with estradiol (E2); and 2) a shorter period of P4 exposure during the growing phase of the ovulatory follicle improves oocyte competence and fertility after fixed-time artificial insemination or superstimulation in cattle. <p>In the first experiment, heifers (n=22) were treated with 100 or 200 µg of GnRH or pretreated with E2 prior to administration of GnRH during high or low circulating P4 concentrations to characterize LH release (Chapter 2). Increasing the dose of GnRH did not alter LH secretion; however, E2 pretreatment overcame the suppressive effect of high P4 on LH secretion. Cattle with lower (n=11) P4 concentrations had higher circulating LH concentrations than those with higher P4 concentrations (n=11), and tended to have higher ovulation rates. <p>Two experiments were conducted to determine the effect of the duration of P4 exposure during the ovulatory wave on fertility followed fixed-time artificial insemination or superstimulation. In the first experiment (Chapter 3), the dominant follicle was allowed to grow for 3 days (n=181) or 6 days (n=184). Six days of growth resulted in a larger dominant follicle, but in both groups, ovulatory follicles had similar capacities to ovulate and establish pregnancy. In the second experiment (Chapter 4), multiple follicles were allowed to grow for 3 or 6 days by 8 or 14 injections of FSH (at 12-hour intervals). There was no difference between groups for ovulation rate or total ova/embryo recovery rate. Although the 3-day group had higher embryo quality at slaughter (4 days after insemination), further development (7, 9, and 10 days after insemination) did not differ among groups. The effect of FSH starvation following 4 days of FSH treatment (Chapter 4) resulted in loss of ovulatory capability. Overall, a shorter duration of P4 exposure during ovulatory follicle growth did not improve fertility after fixed-time AI or oocyte competence after superstimulation.

Objectives were to determine: 1) whether estradiol benzoate (EB) provides a superior alternative to GnRH for synchronizing emergence, growth and maturation of a new follicular wave for fixed timed AI (TAI) in Bos indicus-influenced cattle using CIDR-based protocols, 2) the effect of 48 h calf removal at CIDR removal on the rate of maturational synchrony of the dominant follicle and 3) the effect of varying the magnitude of peak plasma progesterone (P4) concentrations following CIDR insertion on the suppression of FSH and LH secretion in a CIDR-based protocol using EB. In experiment 1, sixty-four Braford (F-1) females were stratified by BCS, parity and days postpartum and assigned randomly to one of four groups in a 2 x 2 factorial arrangement of treatments: 1) Select-Synch + CIDR, 2) Select-Synch + CIDR with 48 h calf removal, 3) E-Synch + CIDR or 4) E-Synch + CIDR with 48 h calf removal. A greater number of cattle in the EB treated group exhibited NFWE compared to the GnRH group, 29 vs 17 cows for EB and GnRH respectively, (P<0.0006). Intervals to NFWE were also greater in EB treated cattle than in GnRH treated cattle, 4.2 vs 2.7 d for EB and GnRH treated cattle respectively, (P<0.0001). Proportions of GnRH- and EB-treated cows ovulating after CIDR removal did not differ. Post-CIDR suckling status did not affect ovulation frequency or interval to ovulation. In experiment 2, eight pubertal (F-1) heifers were used in a Latin Square design with four treatment levels of P4: 1) EB only, 2) EB and new CIDR, 3) EB and new autoclaved CIDR, 4) EB, new autoclaved CIDR and P4 injection at CIDR insertion. Treatments 2 through 4 increased (P < 0.01) mean plasma P4 concentrations compared to treatment 1, with treatment 4 creating the greatest increase in P4 with the longest duration. Suppression of plasma FSH was greatest in group 4 (P<0.08), with mean 60 h concentrations less than in all other groups. Mean concentrations of LH were lesser in group 4 than groups 1 and 2. Frequencies of occurrence of NFWE and ovulation and intervals to NFWE did not differ among treatments. Results indicate that the use of EB and CIDR to synchronize Brahman x Hereford females may provide better synchronization for TAI compared to GnRH and CIDR based protocols.

This dissertation focused on two classes of molecules implicated in processes of implantation and placentation in sheep and pigs. Study one examined the temporal/spatial distribution of several Small Integrin-Binding Ligand, N-Linked Glycoprotein (SIBLING) family members in cyclic and pregnant ovine uterus. Studies two and three evaluated the relationships between progesterone (P4) and estrogen (E2) and their receptors (PGR and ESR1, respectively) on FGF7 mRNA expression within the endometrium and placenta of pigs. Study one showed that dentin sialophosphoprotein (DSPP) was first detected in luminal epithelium (LE) of Day 15 cyclic and pregnant sheep. Stromal expression of DSPP was first detected on Day 20 of pregnancy in stratum compactum and remained prominent in stroma through Day 120. Stromal DSPP protein was positively influenced by the conceptus based upon analysis of a unilaterally pregnant ewe model system. Immunoreactive dentin matrix protein 1 (DMP1), matrix extracellular phospoglycoprotein (MEPE) were localized to the stroma of cyclic and pregnant sheep, however, these proteins appeared to be constitutively expressed. BSP was not detected in ovine endometrium. Study two determined the effects of E2, P4, P4+E2, P4+the PGR antagonist (ZK137, 316), and P4+E2+ZK on FGF7 mRNA expression in uterine LE of ovariectomized pigs. Results indicate that P4 is permissive to FGF7 mRNA expression by down-regulating PGR in LE; P4 stimulates PGR-positive uterine stromal cells to release an as yet unidentified progestamedin that induces FGF7 mRNA expression by LE; E2 and P4 can induce FGF7 mRNA in the absence of PGR rendered nonfunctional by ZK. Study three showed the expression of ESR1, PGR and FGF7 in the uterine and placental tissue of pregnant pigs from Day 20 through 85. Results reveal a positive correlation between stromal cell expression of PGR and FGF7 mRNA which suggests that P4 is permissive to FGF7 mRNA expression by down-regulating PGR in LE. FGF7 mRNA in later pregnancy is maintained by the release of progestamedin from PGR-positive stromal cells. A novel finding was the presence of ESR1 in porcine placenta on Days 20 through Day 85 of pregnancy suggesting that E2 may play important roles in the placental biology of the pig.

No description available.

Introduction. Allopregnanolone and pregnanolone (neuroactive metabolites of progesterone) act as positive modulators of the GABAA receptor system which is the major inhibitory system in CNS. Contradictory results on the effect of GABAA receptor modulators are reported. Beneficial properties such as anaesthesia, sedation, and anxiolysis are reported as well as adverse, anxiogenic and aggressive effects. It has been suggested that GABAA receptor agonists have bimodal effects. Low concentrations increase an adverse, anxiogenic effect, whereas higher concentrations show beneficial, calming properties. Aims. To investigate if progesterone treatment induces adverse mood in postmenopausal women and if the severity in mood symptoms is related to progesterone, allopregnanolone or pregnanolone serum concentrations. To evaluate differences in steroid concentrations induced by different doses and routes of administration of progesterone. Methods. Two randomised, placebo-controlled, double-blind crossover studies of postmenopausal women were performed. Subjects were treated with estradiol continuously. Different doses of progesterone, given vaginally or orally, were added sequentially during the last 14 days of each treatment cycle. Daily symptom ratings were kept using a validated rating scale. Blood samples for progesterone, allopregnanolone and pregnanolone analyses were collected during each treatment cycle. A study regarding the pharmacokinetics after ingestion of low-dose oral progesterone was conducted with postmenopausal women. Blood samples for the analyses of progesterone, allopregnanolone and pregnanolone were collected and pharmacokinetic parameters were calculated. Results. Certain postmenopausal women on sequential HT with vaginal and oral progesterone experience mood deterioration during the progesterone phase while on a low dose of progesterone but not on higher doses or the placebo. Negative mood symptoms occurred when the serum concentration of allopregnanolone was similar to endogenous luteal phase levels, whereas lower and higher concentrations had no effect on mood. Pharmacokinetic analyses show that low-dose oral progesterone can be used as a prodrug to allopregnanolone when the aim is to achieve physiological concentrations of allopregnanolone. Conclusions. A bimodal association between allopregnanolone concentration and adverse mood is observed in postmenopausal women treated with progesterone. The addition of low-dose progesterone to estradiol induces adverse mood in postmenopausal women, whereas higher doses and placebo have no mood-deteriorating effect.

There is a large sex difference in the prevalence of attention deficit disorder; yet, little is known about sex differences in prefrontal attention circuitry. We investigated sex differences in the developmental nicotinic excitation of corticothalamic layer VI neurons, which play an important role in attention. Using whole cell recording in prefrontal brain slices, we examined the inward currents elicited by nicotinic stimulation in rodents. We found a prominent sex difference in the currents during the first postnatal month when males had significantly greater α4β2* nicotinic currents. Immunohistochemical analysis of α4YFP mice revealed no sex difference in the pattern or proportion of YFP-positive neurons in layer VI. Further electrophysiological experiments revealed that progesterone is able to rapidly and significantly suppress nicotinic currents in layer VI neurons. This is the first illustration at a cellular level that prefrontal attention circuitry is differently excited by nicotinic stimulation in males and females during development.

There is a large sex difference in the prevalence of attention deficit disorder; yet, little is known about sex differences in prefrontal attention circuitry. We investigated sex differences in the developmental nicotinic excitation of corticothalamic layer VI neurons, which play an important role in attention. Using whole cell recording in prefrontal brain slices, we examined the inward currents elicited by nicotinic stimulation in rodents. We found a prominent sex difference in the currents during the first postnatal month when males had significantly greater α4β2* nicotinic currents. Immunohistochemical analysis of α4YFP mice revealed no sex difference in the pattern or proportion of YFP-positive neurons in layer VI. Further electrophysiological experiments revealed that progesterone is able to rapidly and significantly suppress nicotinic currents in layer VI neurons. This is the first illustration at a cellular level that prefrontal attention circuitry is differently excited by nicotinic stimulation in males and females during development.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.