Effect of ovariectomy in heart failure-prone SHHF/Mcc-facp rats.

The importance of the loss of ovarian function to the progression of hypertension and heart disease in women is controversial. We investigated whether ovariectomy would accelerate development of hypertension, congestive heart failure, and neurohumoral activation in adult spontaneous hypertension heart failure (SHHF) rats, a genetic model of heart failure. Six months after ovariectomy, no significant differences between control and ovariectomized rats were seen in systolic or diastolic blood pressure, left ventricular fractional shortening by echocardiography, or heart weight.

17 beta-estradiol treatment increases the levels of estrogen receptor and its mRNA in male rat liver.

This study examined estrogen receptor dynamics in the livers of male obese rats (SHHF/Mcc-cp) treated for two weeks with a continuous, low dose of 17 beta-estradiol compared with untreated controls. An increased binding capacity for tritiated 17 beta-estradiol in the cytosol, consistent with binding to the estrogen receptor, was demonstrated in treated males relative to control males (P < 0.01).

Pregnancy-associated, lymphocyte-derived suppressor factor inhibits protein kinase C activity.

For successful allogenic pregnancy to occur, suppression of maternal defense responses toward the fetus are vital. Suppressor factors elaborated by decidual cells or immune cells may facilitate this suppression. In order for appropriate cellular responses to occur an intact signal transduction/second messenger system must be present.

Onset of obesity and puberty in genetically obese SHHF/Mcc-cp rats.

SHHF/Mcc-cp rats, as a model of obesity and diabetes, were followed through breeding and throughout development to determine timing of obesity and sexual development. The obesity or corpulency gene (cp) follows recessive transmission characteristics with no segregation between sexes. Although the frequency of litter sizes was different, the mean litter size of heterozygous mating (8.

The lack of direct effects of a monoclonal antibody against murine T-cell suppressor factor on murine embryo development in vitro.

In previous studies, we reported that the injection of monoclonal antibody 14-30, specific for a T-cell suppressor factor (TSF), into mice during early stages of pregnancy could decrease the percentage of females that maintained pregnancy. In addition, further work has demonstrated the presence of an immunoreactive protein in fetal and maternal tissues with physiochemical properties similar to TSF. However, one alternate explanation for the antipregnancy effects of the injections of monoclonal antibody, not related to a specific role for TSF in early pregnancy, is the possibility of direct effects upon the embryo or embryonic antigens that prevent continued embryonic development.

Embryo implantation associated with increase in T-cell suppressor factor in the uterus and spleen of mice.

The concentrations of T-cell suppressor factor (TsF) were examined by competitive binding assays in the uterus, spleen, and regional lymph nodes draining the uterus in Day-5 pregnant mice or in ovariectomized mice given hormone treatments to induce conditions of delayed implantation or implantation. The amounts of immunoreactive TsF on Day 5 of pregnancy were 2.055 +/- 0.

Hereditary pituitary prolactinomas: a new rat model.

Pituitary adenomas are known to occur spontaneously in several rat strains, especially during aging. Here we report the occurrence of adenomas (prolactinomas) in a new rat model at an early age. The adenomas were characterized by light and electron microscopy and histochemically by immunoperoxidase methods using specific antisera.

T-cell suppressor factors play an integral role in preventing fetal rejection.

In previous studies we showed that the blocking of T-cell suppressor factors (TsF) with monoclonal antibody could completely ablate pregnancy, and demonstrated the presence of TsF in fetal and maternal tissues. In our current study we used a monoclonal antibody specific for TsF to determine the time during gestation when TsF is most integral in the maintenance of pregnancy. Significant decreases in the number of viable pregnancies when monoclonal antibody was administered on days 3, 4 and 5 were demonstrated.

Induction of abortion in mice with a monoclonal antibody specific for suppressor T-lymphocyte molecules.

A monoclonal antibody, mAb 14-30, which binds T-cell produced suppressor factors (TsF) was used to study the possibility that molecules produced by suppressor T-cells play a role in maintaining pregnancy, presumably by protecting the fetus from the maternal immune system. Female mice were injected with mAb 14-30 at various times after mating. Overall, only 14% of the expected 68% of the mated and treated females were pregnant at term.

Oestradiol synthesis by granulosa cells from immature rats treated with pregnant mare's serum gonadotrophin.

Granulosa cells harvested from follicles in hypophysectomized or intact immature rats treated with 20 IU of pregnant mare's serum gonadotrophin (PMS) produced immunoreactive oestradiol (E2) when incubated in Krebs Ringer bicarbonate buffer containing an NADPH generating system; inclusion of steroid substrates in the medium increased the rate of synthesis. Further, tritiated E2 was synthesized when labelled progesterone was used as substrate. Granulosa cells removed from pre-ovulatory follicles on the morning of pro-oestrus in adult females also produced E2 in vitro.

Aromatase activity in the rabbit blastocyst.

Rabbit blastocysts were homogenized by sonication, and centrifuged at 105 000 g for 60 min. The pellet was resuspended and incubated in phosphate buffer containing [1 beta-3H]testosterone and a NADPH generating system. The amount of 3H2O produced was determined by liquid scintillation counting.

Catechol estradiol induced implantation in the mouse.

Induction of implantation is among the most sensitive responses to estrogens. The ability of catechol estradiols, 4-hydroxy-estradiol-17 beta (4-OH-E2) and 2-hydroxy-estradiol-17 beta (2-OH-E2), to induce implantation in ovariectomized pregnant mice was compared to that of estradiol-17 beta. Delayed implantation was maintained by the daily administration of 2 mg of progesterone.

Phospholipase A2 activity in the rat uterus: modulation by steroid hormones.

Phospholipase A2 (PLA2), an enzyme which provides free arachidonic acid for the synthesis of prostaglandins (PG), has been studied in the rat uterus under various experimental conditions. Uterine PLA2 activity increased 14 fold in hypophysectomized rats implanted with Silastic capsules containing estradiol-17 beta as compared to those treated with oil vehicle. Dexamethasone treatment reduced the PLA2 activity induced by estrogen by 78%.

In-vitro zona-lytic activity in uterine fluid from ovariectomized mice treated with oestradiol-17 beta and progesterone.

Mouse embryos collected before implantation were incubated in vitro for 24 h with fluid rinsed from the uteri of ovariectomized female mice injected with progesterone, oestradiol-17 beta + progesterone, oestradiol-17 beta + progesterone, or oestradiol-17 beta alone. Although none of the zonae was completely dissolved, those incubated in fluid from animals treated with oestradiol + progesterone were subsequently more soluble in sodium thiocyanate (NaSCN) than those incubated similarly in control buffer, indicating a sublytic change during the incubation with uterine washings. Zonae incubated in fluid from animals injected with either hormone alone did not undergo such a change.

Steroid 17 alpha-hydroxylase activity of ovarian granulosa cells from hypophysectomized immature rats treated with pregnant mare's serum gonadotropin (PMS).

Immature hypophysectomized rats were injected with 2mg of diethylstilbestrol to increase granulosa cell numbers and with 20 IU of PMS to stimulate ovarian growth. Steroid 17 alpha-hydroxylase activity of cultured granulosa cell, harvested from mature follicles 48 h after injection of PMS, was demonstrated using a tritium exchange assay with 17 alpha 3H-pregneneolone as substrate. For comparison, aromatase activity of the same cells was examined by a similar assay using 1 beta 3H-testosterone as the substrate.

Lysis of the zona pellucida and attachment of embryos to the uterine epithelium in ovariectomized mice treated with oestradiol-17 beta and progesterone.

Preimplantation mouse embryos with intact zonae pellucidae were transferred into the uteri of ovariectomized females treated with progesterone, oestradiol-17 beta plus progesterone, or oestradiol-17 beta alone; the disappearance of zonae from the uterine lumen was used to determine the presence of 'zona-lytic' activity in situ. Lysis of zonae did not occur in animals treated with progesterone or oestradiol-17 beta alone. However, lysis did not occur when oestradiol-17 beta was combined with progesterone; 'zona-lytic' activity reached peak levels within 12 to 24 h, then decreased.

The volume of uterine fluid in 'implanting' and 'delayed implanting' mice.

A variation of the dye dilution technique was used to determine the volume of uterine fluid in 'implanting' and 'delayed implanting' mice. The method involves rinsing Krebs-Ringer-bicarbonate buffer containing [methyl-14C]methylated-BSA through the uterine lumen and using the resulting decrease in concentration of the BSA to calculate the volume of uterine fluid. The results indicated that the volume of uterine fluid was essentially the same in 'implanting' and 'delayed implanting' mice (i.