The facilitative influence of experiential factors on the parental behavior of male mice (Mus musculus): (i) The effects of the experience of copulation and cohabitation with a pregnant female

Effects of the experience of copulation and cohabitation with a pregnant female on male parental behavior were examined in ICR-strain male mice. The experience of copulation and/or cohabitation with a pregnant female promoted parental behavior, although the cohabitation with a pregnant female per se failed to inhibit infanticide in male mice. Therefore, it is possible that the facilitation of parental behavior is caused by a motivation independent from that of the inhibition of infanticide in male mice. As to the facilitation of parental behavior, the effect of copulation was stronger than that of cohabitation with a pregnant female, and these 2 effects seem to be additive. It is possible that there are 2 independent mechanisms for the facilitation of parental behavior in male mice.     

Effect of pregnancy, postnatal growth, and gender on renal sulfate transport.

Serum sulfate concentrations are increased in infants, young children, and pregnant women, compared with adult values. The objective of this investigation was to examine the influences of age, gender, and pregnancy on renal sulfate transport using guinea pigs as an animal model. Membrane vesicles were isolated from the kidney cortex of male animals at four different ages, from male and female adult animals, and from pregnant and nonpregnant female animals. There were no significant differences in marker enzymes for the brush-border membrane (BBM) or basolateral membrane (BLM) among all groups examined. Uptake was determined by a rapid filtration method and membrane fluidity by measuring the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene. The Vmax values for Na+ /sulfate co-transport in BBM were significantly increased with decreasing age, whereas the Km for this process was unchanged. The Vmax and Km for Na + /sulfate co-transport in BBM of pregnant animals were significantly higher than the values in the nonpregnant group. Bicarbonate-driven anion exchange of sulfate in BLM was not different among the different age groups. The Vmax for the bicarbonate/sulfate exchange process in BLM was not different between pregnant and nonpregnant groups; however, the Km for this process in BLM of pregnant animals was significantly greater than the value in nonpregnant animals. There were no gender-related differences in sulfate transport in BBM or BLM isolated from adult male and female animals. Renal BBM fluidity was increased with decreasing age and in pregnant animals, suggesting that altered membrane fluidity may represent one possible mechanism to explain the increased sodium/sulfate uptake in young and pregnant animals. The higher Vmax for Na+/sulfate co-transport in young and pregnant animals suggests that there is an increased density of co-transporter protein or an increase in the rate of movement of the carrier protein (i.e., turnover) once loaded with sodium and sulfate. This increased conservation of inorganic sulfate in young and pregnant guinea pigs may be related to the increased demand for sulfated substrates, such as sulfated glycosaminoglycans, during growth and development.     

大熊猫妊娠及产仔行为观察

对人工饲养下８ 只次怀孕产仔大熊猫的妊娠反应、产仔行为和７ 只次配种未孕大熊猫行为进行比较研究表明, 受配雌兽到一定时间后摄取窝头情况可作为判断是否怀孕及预测产期的重要行为指标。怀孕产仔大熊猫和假孕大熊猫都有类似的反应： 减食, 拒食窝头、竹, 活动量明显减少, 乳房、外阴发生较大变化, 舔外阴、含竹作巢等。但前者拒食窝头并持续到产后一段时间, 后者有的在拒食窝头的中途出现摄食窝头的行为; 有的减食或拒食不久又摄食窝头－ 再拒食－ 再摄食, 活动量减少, 外阴、乳房仅有微弱变化。产仔大熊猫的预产期在减食窝头后２５ 天左右或拒食窝头后的２１ 天左右。大熊猫产仔期破羊水次数与每胎产仔只数有关。     

Reproductive performance of the wild white-lipped peccary (<Emphasis Type="Italic">Tayassu pecari</Emphasis>) female in the Peruvian Amazon

The ability of any species to support high hunting pressures depends on its reproductive efficiency. Based on the gross anatomic examination of 208 adult female reproductive tracts, we characterised the reproductive biology of the wild white-lipped peccary in the northeastern Peruvian Amazon. White-lipped peccary apparently bred year round in the northeastern Peruvian Amazon, and the number of pregnant females was 80 (38.4%). Mean ovulation rate was 2.09 ± 0.47 CLs, and litter size was 1.60 ± 0.49 embryos or foetuses per pregnant female. A phenomenon of embryo migration was observed in the 27.5% of pregnant females. Estimations suggest 0.89 births per year and a yearly reproductive production of 1.42 piglets per pregnant female. Females in the late pregnancy stage showed a higher hunting vulnerability that could be an important restrictive factor for the reproductive efficiency of the wild white-lipped peccary populations in the Peruvian Amazon.     

First observation of the courtship behaviour of the giant devil ray Mobula mobular (Myliobatiformes: Mobulidae)

Courtship behaviour of the giant devil ray Mobula mobular is described from northern New Zealand, temperate southwest Pacific Ocean, for the first time. A mating train consisting of a full-term pregnant female and up to four males was observed over a period of 147 minutes. Their behaviour was similar to courtship behaviour observed in other large mobulids. Biting of the female was not observed, possibly due to the female’s use of the surface to prevent males positioning themselves above her. However, the lead male pressed the female’s abdomen and underside each time the female reached or stopped at the surface. The occurrence of pregnant females and mating behaviour off northern North Island confirms breeding occurs in New Zealand waters.     

The embryotoxicity of gossypol

In utero development was analyzed in pregnancies that resulted from matings between gossypol-treated male rats and untreated female rats and in pregnancies in which gossypol was administered to the pregnant rat only. Gossypol treatment of males had no effect on the outcome of pregnancy. There was no significant effect on resorption, fetal growth, or malformation rate. Similarly, gossypol administered to pregnant dams at stages during organogenesis had no observable effect on pregnancy. Under the conditions of this experiment, gossypol administered to either the breeding male rat or the pregnant female rat had no demonstrable adverse effect on development in utero.     

Retinal Vein Occlusion and Pregnancy,Pre-Eclampsia,and Eclampsia: The Results from a Nationwide,Population-Based Study Using the National Claim Database

Objective

To investigate the incidence of retinal vein occlusion (RVO) in pregnant women and in the subpopulation of pregnant women with pre-eclampsia/eclampsia compared to that in the age-matched general female population to determine if there is increased risk of RVO in pregnancy.

Design

Nationwide population-based retrospective study using data entered into the Korean national health claims database from 2007 to 2011.

Setting and Participants

Of the incident RVO cases in the database, RVO cases that occurred during the pregnancy-associated period, which spanned a 52-week period from 40-weeks-before to 12-weeks-after childbirth, were identified. Of these cases, the presence of pre-eclampsia/eclampsia was determined.

Main Outcome and Measure

The standardized incidence ratios (SIRs) of RVO in the general pregnant population and in the pregnant population with pre-eclampsia/eclampsia were determined with respect to the age-matched general female population.

Results

Pregnancy-related RVO was identified in 33 cases from the 1.8 million women who experience childbirth during the study period, while the expected number of cases calculated by the direct standardization to the age-matched general population was 113. Of the 33 patients, 12 patients (36.4%) had pre-eclampsia or eclampsia. The SIR for the general pregnant population in reference to the age-matched general female population was 0.29 (95% CI, 0.20–0.41). In contrast, the SIR for the pregnant population with pre-eclampsia/eclampsia in reference to the age-matched general female population and the age-matched general pregnant population was 67.50 (95% CI, 34.88–117.92) and 246.50 (95% CI, 127.37–430.59), respectively.

Conclusions and Relevance

The results suggest that pre-eclampsia/eclampsia is a risk factor for RVO, while pregnancy itself may not be a risk factor for RVO.     

Influence of pregnancy and sex steroids on concentration, motor effect and receptor binding of VIP in the rabbit female genital tract

The influence of sex steroid and pregnancy on the tissue concentration, uterine motor effect and receptor binding of VIP has been studied in the female genital tract of pregnant rabbits and oophorectomized rabbits during progesterone and/or oestrogen substitution. The concentration of immunoreactive VIP was high in the vagina and cervix, and lower in the uterine body of both pregnant and non-pregnant rabbits. A significant decrease in the VIP concentration (pmol/g wet weight) of the uterine body was observed toward term of pregnancy. The total uterine content of VIP, however, seems unchanged. Treatment of oophorectomized rabbits with ovarian steroids had no effect on the VIP concentration. The sensitivity for and potency of VIP on the relaxation of uterine muscle was significantly higher in oophorectomized rabbits treated with a combination of progesterone and oestrogen than in control rabbits. No difference was observed between non-pregnant and pregnant rabbits. The degradation and binding affinity for 125I-labelled VIP was highest in oophorectomized rabbits substituted with both oestrogen and progesterone. In the pregnant rabbits, the amount of receptors was decreased near term. In conclusion, sex steroids are able to influence the motor effect of VIP at the receptor level, but have no effect on the VIP concentration in the female genital tract.     

Viability Costs of Reproduction and Behavioral Compensation in Western Mosquitofish (Gambusia affinis)

The cost of reproduction hypothesis suggests that current reproduction has inherent tradeoffs with future reproduction. These tradeoffs can be both in the form of energy allocated to current offspring as opposed to somatic maintenance and future reproduction (allocation costs), or as an increase in mortality as a result of morphological or physiological changes related to reproduction (viability costs). Individuals may be able to decrease viability costs by altering behavior. Female western mosquitofish, Gambusia affinis experience a reduction in swimming ability as a consequence of pregnancy. We test for a viability cost of reproduction, and for behavioral compensation in pregnant female G. affinis by measuring survival of females in early and later stages of pregnancy when exposed to predation. Late-stage pregnant females experience a 70% greater probability of mortality compared to early-stage pregnant females. The presence of a refuge roughly doubled the odds of survival of both early and late-stage pregnant females. However, there was no interaction between refuge availability and stage of pregnancy. These data do not provide evidence for behavioral compensation by female G. affinis for elevated viability costs incurred during later stages of pregnancy. Behavioral compensation may be constrained by other aspects of the cost of reproduction.     

Reproductive performance of the wild collared peccary (Tayassu tajacu) female in the Peruvian Amazon

Based on the gross anatomic examination of 218 adult female reproductive tracts, we characterised the reproductive biology of the wild collared peccary in the Northeastern Peruvian Amazon. Collared peccary apparently breed year round in the Northeastern Peruvian Amazon and the number of pregnant females was 92 (42.2%). Estimations suggest 1.12 births/year and a yearly reproductive production of 1.98 piglets per pregnant female. Collared peccary females presented a mean ovulation rate of 2.25 ± 0.58 CLs, a litter size of 1.77 ± 0.48 embryos or foetuses and a reproductive wastage of 0.45 ± 0.65 (21.3%) oocytes or embryos per pregnant female. A phenomenon of embryo migration was observed in 31.8% of pregnant females. This study provides reproductive information that should be taken into account in management plans.     

Potentiation by caffeine of the frequencies of micronuclei induced by mitomycin C and cyclophosphamide in young mice

Employing the micronucleus test in mouse bone marrow and in fetal mouse liver, the possible clastogenicity of caffeine as well as its influence on MMC- and CP-induced micronucleus levels were studied. The treatment of male and female C57Bl or BDF1 (C57Bl x DBA2) mice with caffeine (1 or 3 x 50 mg/kg and 100 mg/kg, s.c.) had no clastogenic effect in mouse bone marrow or in the fetal livers and maternal bone marrow when pregnant mice were injected with caffeine on day 16-17 of gestation. MMC (2.0 mg/kg, i.p.) increased up to 10-30-fold the number of MNPCEs in bone marrow compared to a 3-7 fold elevation of MNPCEs in fetal liver. A similar effect was also established in pregnant mice treated with CP (30 mg/kg, i.p.). No significant sex differences in spontaneous and MMC- or CP-induced MNPCEs levels were established in C57Bl and BDF1 mice. However, a significantly higher spontaneous rate of MNPCEs as well as a better-expressed responsiveness to the clastogenic activity of MMC and CP were established in C57Bl compared to BDF1 mice. The pregnancy had no effect on MMC- or CP-induced clastogenicity although a tendency to a decreased sensitivity to the damaging activity of MMC seemed to be detected in pregnant C57Bl mice compared to virgin female animals. The combined treatment of mice with caffeine (3 x 100 mg/kg) and MMC or CP caused an up to 45-49% potentiation of clastogenesis in the bone marrow of male, female and pregnant female C57Bl and BDF1 mice but not in fetal mouse livers.     

Concentration of kininogens and low molecular kininogen antigen in plasma of pregnant rabbits and newborn progeny in health and following intravenous infusion of purified thrombin

High levels of trypsin-releasing kinin and low molecular plasma kininogen antigen were detected in plasma of pregnant female rabbits. Respective values in plasma of their new born progeny was 2.7 times lower than that in maternal plasma. Intravenous infusion of the highly purified bovine thrombin administered to pregnant female rabbits markedly decreased plasma fibrinogen platelet count and increased fibrinogen/fibrin degradation products in blood serum. A marked decrease of trypsin-releasing kinin plasma levels accompanied these changes. No changes in the kininogen antigen levels were seen during the same experiments. Thrombin infusions administered to pregnant female rabbits did not produce measurable changes in trypsin-releasing kinin levels and plasma low molecular kininogen antigen in the progeny obtained for the investigations with the aid of cesarean section.     

Effect of pregnancy on joint contracture in the rat knee.

As there is evidence that ligamentous laxity is affected by the female hormones, we hypothesized that hormonal changes occurring during pregnancy could have a therapeutic role in preventing the development of a joint contracture. Knee joint contractures were created in pregnant and nonpregnant rats. After 2 wk of immobilization, the degree of contracture was measured with structural properties of the medial collateral and anterior cruciate ligaments and the pubic symphysis. Although not statistically significant, there was a general trend toward reduced contracture in pregnant compared with nonpregnant rats. Cutting the posterior capsule significantly decreased contracture for both the pregnant and nonpregnant groups, confirming the contribution of capsular structures to contracture. Ultimate loads of the medial collateral and anterior cruciate ligaments significantly decreased after immobilization compared with control, but there was no significant effect due to pregnancy. Stiffness and ultimate load of the pubic symphysis were not significantly different between pregnant and nonpregnant groups. The trend toward reduced contracture with pregnancy points toward a possible therapeutic role for female hormones in the prevention of postoperative and/or posttraumatic joint contracture.     

Prevalence and avidity of human herpesvirus-6 specific IgG antibodies in pregnant women in Hungary

The prevalence, the level and the avidity of human herpesvirus-6 (HHV-6) specific IgG were examined in pregnant women and age-matched female blood donors. The study group consisted of 180 women (age 14-45); 60 women with normal pregnancy, 60 pregnant women with fetuses suspected of having any viral infection and 60 healthy blood donors with no history of pregnancy. Plasma or serum samples were tested for HHV-6 IgG antibodies by an immunofluorescence assay. Ninety-eight percent of blood donors and 97% of 120 pregnant women had IgG antibodies to HHV-6. The rate of seropositivity in women with normal pregnancies and women with fetuses suspected to have viral infection was the same. Pregnant women (n = 120) had significantly lower antibody titer than blood donors. No significant differences were found in the same respect between the two groups of pregnant women. Low avidity of IgG antibodies to HHV-6 was detected in 5% of pregnant women.     

Progesterone metabolism by major salivary glands of rat--I. Submandibular and sublingual glands

The metabolism of progesterone by the submandibular and sublingual salivary glands of female (nonpregnant and pregnant) and male rats was studied. The metabolism was in both sexes significantly greater in submandibular than in sublingual glands. Sex differences were not seen in sublingual glands but less metabolism was found in homogenates and microsomal fractions of female (nonpregnant and pregnant) submandibular glands compared to that of males. The metabolism did not differ between pregnant and nonpregnant female rats. The metabolites were mainly 5 alpha-pregnane-compounds. On the basis of the metabolites identified it can be concluded that rat submandibular and sublingual glands contain at least 3 alpha-, 3 beta-, 20 alpha- and 20 beta-hydroxysteroid dehydrogenase, 5 alpha- and 5 beta-steroid hydrogenase and 17 alpha-steroid hydroxylase activity. 5 alpha-steroid hydrogenase activity was significantly higher in all preparations of male submandibular glands than in females. In sublingual glands some enzyme activities showed pregnancy-related decreased.     

Neutralization of pregnancy-preventing activity of cabergoline, a dopamine agonist with progesterone

Cabergoline (Cab), a dopamine agonist, inhibits the production and/or release of prolactin and reduces progesterone biosynthesis. Cab at doses of 20 microg/kg/d and higher administered on Days 1, 2 and 3 of pregnancy prevented implantation of fertilized ova in all treated female rats. The pregnancy-preventing activity of Cab is attributed to a deficiency of progesterone since estradiol levels remain unchanged. To validate the hypothesis that progesterone deficiency is the cause of the infertility, exogenous progesterone was administered to Cab-treated pregnant female rats and their fertility assessed. Progesterone at a dose of 5 mg/kg/d sc was administered on Days 1 to 7 of pregnancy to female rats treated with Cab (20 and 60 microg/kg/d) on Days 1, 2 and 3 of pregnancy. All progesterone-treated animals became pregnant, and all mated female rats treated with Cab (60 microg/kg/d) and progesterone (5 mg/kg/d) on Days 1 to 7 inclusive became pregnant. In conclusion, progesterone can neutralize the pregnancy preventing activity of Cab. Pregnant female rats treated with Cab can be used to assay for progestagenic activity of compounds.     

Response to starvation of hepatic carnitine palmitoyltransferase activity and its regulation by malonyl-CoA. Sex differences and effects of pregnancy.

1. Hepatic carnitine palmitoyltransferase activity was measured over a range of concentrations of palmitoyl-CoA and in the presence of several concentrations of the inhibitor malonyl-CoA. These measurements were made in mitochondria obtained from the livers of fed and starved (24 h) virgin female and fed and starved pregnant rats. 2. In the fed state overt carnitine palmitoyltransferase activity was significantly lower in virgin females than in age-matched male rats. 3. Starvation increased overt carnitine palmitoyltransferase activity in both virgin and pregnant females. This increase was larger than in the male and was greater in pregnant than in virgin females. 4. In the fed state pregnancy had no effect on the Hill coefficient or the [S]0.5 when palmitoyl-CoA was varied as substrate. Pregnancy did not alter the sensitivity of the enzyme to inhibition by malonyl-CoA. 5. Starvation decreased the sensitivity of the enzyme to malonyl-CoA. The change in sensitivity was similar in male, virgin female and pregnant rats. 6. The possible relevance of these findings to known sex differences and changes with pregnancy in hepatic fatty acid oxidation and esterification are discussed.     

Cumulation of active metabolites of levo-alpha-acetylmethadol in the rat fetus and neonate

Levo-alpha-acetylmethadol (LAAM, 0.2 or 2.0 mg/kg/day) was orally administered to female Sprague-Dawley rats for one month prior to and throughout pregnancy. The rats were killed on the 18th day of gestation along with a group of 18-day pregnant females given a single oral 2.0 mg/kg dose of LAAM 24 hours earlier. Although cumulation of LAAM or its active metabolites was not seen in plasma or brain of pregnant rats given drug chronically, significant cumulation was observed in whole fetus and in fetal brain. In addition, a 2–3 fold elevation in the concentrations, and an even greater elevation of total content, was noted in the newborn pup. These data suggest that opiate intoxication soon after birth may be a factor responsible for the increased morbidity and mortality of rat pups prenatally exposed to LAAM.     

Serum prolactin concentrations and the initiation of maternal behavior in the rat

Maternal behavior and serum prolactin were measured in pregnant and virgin female rats. Pregnant rats were either ovariectomized or shamovariectomized on Day 17 of pregnancy, while virgin females were ovariectomized at the same age. Two days after surgery nests were rated and the three treatment groups were tested for responsiveness to rat pups. Both pregnant treatment groups built superior nests compared to the virgin group and also responded more frequently to rat pups within a 1 hr test period than the virgin controls. In addition, significantly more ovariectomized pregnant subjects responded to pups than did intact pregnant females. Serum prolactin levels did not differ among the three treatments nor did exposure to pups affect serum prolactin levels. In each treatment group serum prolactin was less than 15 ng/ml, well below the 139.7 ng/ml mean found on Day 23 of pregnancy. These data suggest that high levels of serum prolactin during late pregnancy are not essential for the initiation of maternal behavior in the rat.