Effects of space flight on ovarian-hypophyseal function in postpartum rats.

The effect of space flight in a National Aeronautics and Space Administration (NASA) shuttle was studied in pregnant rats. Rats were launched on day 9 of gestation and recovered on day 20 of gestation. On day 20 of gestation, rats were unilaterally hysterectomized and subsequently allowed to go to term and deliver vaginally. There was no effect of space flight on pituitary and ovary mass postpartum. In addition, space flight did not alter healthy and atretic ovarian antral follicle populations, fetal wastage in utero, plasma concentrations of progesterone and luteinizing hormone (LH) or pituitary content of follicle stimulating hormone (FSH). Space flight significantly increased plasma concentrations of FSH and decreased pituitary content of LH at the postpartum sampling time. Collectively, these data show that space flight, initiated during the postimplantation period of pregnancy, and concluded before parturition, is compatible with maintenance of pregnancy and has minimal effects on postpartum hypophyseal parameters; however, none of the ovarian parameters examined was altered by space flight.

Effect of prior nicotine treatment on drug induced changes in serum LH concentrations in rats.

The effect of daily injections of nicotine on drug induced changes in LH secretion was investigated in male rats. Daily administration of nicotine for 7 days resulted in decreased basal serum LH concentrations. Nicotine treatment blocked naloxone induced LH release and reduced LHRH induced increases in serum LH. Clonidine induced increases in serum LH were not altered by nicotine treatment and haloperidol treatment did not alter nicotine induced decreases in serum LH. In an acute study nicotine blocked LH secretion induced by the long acting opioid antagonist naltrexone. Collectively these results indicate that opioidergic neurons are involved in the reduction in serum LH that occurs following nicotine. They also indicate that chronic nicotine treatment can reduce the pituitary gland response to LHRH.

Premature rupture of the membranes between 20 and 25 weeks' gestation: role of amniotic fluid volume in perinatal outcome.

OBJECTIVE: Our purpose was to prospectively study the relationship between amniotic fluid volume and perinatal outcome in pregnancies complicated by premature rupture of the membranes before fetal viability. STUDY DESIGN: The study population consisted of 178 singleton pregnancies with premature rupture of membranes between 20 and 25 weeks' gestation who were managed expectantly. Serial amniotic fluid volume measurements were made and their relationship to the neonatal survival rate, incidence of chorioamnionitis, and other perinatal outcomes was determined. RESULTS: Seventy-four patients were delivered before 25 weeks of gestation and only five infants (6.7%) survived. In contrast, 104 patients were delivered between 26 and 34 weeks, and 93 infants (89.4%) survived (p < 0.001). There were 107 pregnancies with adequate amniotic fluid volume after premature rupture of membranes on admission. Of these 16 patients were delivered before 25 weeks of gestation, and the remaining 91 patients were able to carry their pregnancies beyond 25 weeks of gestation. This was significantly different from 71 patients who demonstrated inadequate amniotic fluid volume on admission to the hospital, of whom 58 were delivered before 25 weeks and only 13 continued the pregnancy beyond 25 weeks (p < 0.05). At gestations between 26 and 34 weeks chorioamnionitis occurred in 22 of 91 (24.1%) patients with adequate amniotic fluid volume versus nine of 13 patients (69.2%) with inadequate amniotic fluid volume (p < 0.001). The incidence of perinatal death for pregnancies between 26 and 34 weeks with adequate versus inadequate amniotic fluid volume was 2.1% and 69.2%, respectively (p > 0.001). Overall survival rate and incidence of chorioamnionitis were 55% and 26.4%, respectively. CONCLUSIONS: Delivery of pregnancies between 20 and 25 weeks of gestation with premature rupture of membranes carries very high risk of neonatal mortality. The results of this study suggest that women with adequate amniotic fluid volume have a better chance to continue their pregnancy beyond 25 weeks of gestation and have a higher neonatal survival rate than those with inadequate amniotic fluid volume. The incidence of perinatal death and chorioamnionitis in patients who carry a pregnancy beyond 25 weeks is correlated with inadequate amniotic fluid volume.

Dorsal rhizotomy does not alter rat estrous cycles or ovarian compensatory responses.

Rats were subjected to right side dorsal rhizotomy of spinal nerves T12-L2 and ipsi- or contralateral unilateral ovariectomy at estrus (day 1). Estrous cycles were recorded daily, and on day 15 the remaining ovary was removed and weighed. Antral follicles were counted in representative day 1 and day 15 ovaries. Dorsal rhizotomy did not affect estrous cycles during the period after surgery. Also dorsal rhizotomy did not alter ipsilateral ovarian hypertrophy or follicular activation following unilateral ovariectomy. Thus, although the major portion of the ovarian sensory innervation is via the lesioned segments, interruption of these segments centrally does not alter compensatory ovarian responses subsequent to unilateral ovariectomy.

Naltrexone treatment attenuates the inhibitory effect of nicotine treatment on serum LH in rats.

The hypothesis that endogenous opioids might have a role in mediating the suppressive effects of nicotine on serum LH concentrations in rats was investigated. Naltrexone treatment prevented the inhibitory effect of high doses of nicotine on serum LH concentrations. Nicotine treatment also prevented the stimulatory effect of naltrexone on serum LH concentrations. These results suggest that the inhibitory effects of nicotine on serum LH concentrations involve an opioidergic component.

Endocrine parameters associated with disruption of parturition after bilateral pelvic neurectomy.

Bilateral lesions of the pelvic nerve (BLPN) result in dystocia, but the processes which control this effect are not fully understood. Plasma progesterone, relaxin, and luteinizing hormone (LH) concentrations were measured in blood samples taken in the morning (AM) and evening (PM) of Days 20-23 of gestation from rats with BLPN or sham neurectomy. Ten of 11 sham-operated control animals delivered their entire litters by Day 23 of gestation, but animals with BLPN did not complete parturition by Day 23 when they were sacrificed. Progesterone concentrations were greater in rats with BLPN than in sham-operated rats on Day 20 PM and Day 21 AM, but hormone concentrations declined to minimal values by Day 22 in both groups. Relaxin concentrations were greater in rats with BLPN than in sham-operated rats on Day 21 PM. Thereafter, relaxin concentrations decreased to reach minimum values on Day 23 in both groups. LH concentrations were low throughout the period of study in rats with BLPN; however, a postpartum LH surge was detected in all sham-operated animals. Data from this study indicate that the pelvic nerve does not control parturition by modulating serum relaxin and progesterone concentrations; however, these data suggest that impulses carried by the pelvic nerve influence ovarian secretion of these hormones. In addition, these data indicate that the pelvic nerve transmits stimuli from the cervix to the hypothalamus to facilitate the postpartum LH surge.

Effect of cyclosporin treatment on luteinizing hormone and prolactin.

The effect of cyclosporin A (CsA) treatment on LH and prolactin was investigated. Chronic daily administration of an immunosuppressive dose of CsA (1.5 mg/100g bw) increased serum LH concentrations and pituitary gland LH content. CsA treatment also resulted in increased serum testosterone. Immunosuppressive doses of CsA had no effect on serum prolactin or pituitary gland prolactin content. Acute administration of low doses of 0.12, 1.2, 12 and 120ug CsA/100g bw had no effect on serum LH or prolactin. These results suggest that administration of immunosuppressive doses of CsA alters serum and pituitary LH and serum testosterone but not prolactin.

Alteration of the mammotroph Golgi complex by the dopamine agonist 2 Br-alpha-ergocryptine (CB-154) in ovariectomized estrogen primed rats.

The present study examined the acute effects of 2 Br-alpha-ergocryptine (CB-154, a dopamine agonist) on mammotroph organelles during prolactin (PRL) suppression. Ovariectomized estrogen-primed rats received a single injection (sc) of 0.5 mg CB-154 and the animals were killed at intervals following injection. The anterior pituitary glands were fixed for electron microscopy and immunocytochemistry was used to confirm mammotroph identification. Serum PRL levels were determined by RIA. Following CB-154 administration, serum PRL was significantly (P less than 0.05) reduced within 15 minutes and was suppressed (P less than 0.01) to ovariectomized levels at 2 and 6 hours. A stereological analysis of mammotrophs in the central regions of the anterior pituitary showed that the Golgi complex volume was significantly (P less than 0.05) reduced at 2 hours after CB-154 treatment. However, the Golgi complex volume had recovered by 6 hours post CB-154 injection. In addition, the volumes of the mammotroph cells, the mature secretory granules, and the secondary lysosomes had significantly increased by 6 hours. There were no significant changes in any of the organelles following CB-154 in the mammotrophs from the peripheral regions of the gland. These studies show that the Golgi complex is especially susceptible to acute morphological changes induced by bromocryptine and that the mammotrophs in the central regions are more responsive to CB-154 than those in the peripheral regions.

Effects of peripheral nerve lesions during pregnancy on parturition in rats.

Bilateral section of either the sensory or motor branch of the pelvic nerve or pudendal nerve was performed in rats on days 8-10 of pregnancy, and the effects on delivery were observed. Bilateral resection of the sensory branch of the pelvic nerve reduced the number of live pups per litter, and increased the number of stillbirths and the number of fetuses retained in utero per litter at day 24. Sectioning motor components of the pelvic nerve, or both motor and sensory components of the pudendal nerve, had no effects on delivery in rats. We conclude that of the peripheral nerves evaluated in this study, only the sensory branch of the pelvic nerve is required for normal vaginal delivery in this species.

Effect of abdominal vagotomy at proestrus on ovarian weight, ovarian antral follicles, and serum levels of gonadotropins, estradiol, and testosterone in the rat.

The effects of abdominal vagotomy at proestrus on ovarian weight and antral follicles greater than 150 microns diameter and on serum levels of gonadotropins and testosterone were assessed 24 and 48 h and 4 and 8 days after surgery. Serum levels of estradiol were assessed at 4 and 8 days. Vagotomy increased ovarian weight at 48 h, decreased ovarian weight at 4 days, but had no effect by day 8. Vagotomy increased healthy antral follicles 151-394 microns diameter at 24 and 48 h and increased atresia in this size range at 4 and 8 days. Vagotomy decreased healthy follicles 151-384 microns at day 8. Vagotomy decreased healthy follicles 395-570 microns at 24 h and decreased atretic follicles at 48 h. Vagotomy decreased the largest (over 570 micron diameter) healthy follicles at 24 h and 8 days. Vagotomy decreased basal serum LH levels at 48 h and 8 days. (In contrast, vagotomy increased FSH at 24 h). There was no effect on blood levels of estradiol and testosterone. These findings are discussed in relation to the hypothesis that the vagus nerve is a component of the hypothalamo-hypophyseal-ovarian axis.

The effects of vagotomy on compensatory ovarian hypertrophy and follicular activation after unilateral ovariectomy.

Following unilateral ovariectomy in the rat, the remaining ovary undergoes rapid compensatory changes including an increase in the number of antral follicles (follicular activation) and an increase in ovarian weight (compensatory ovarian hypertrophy). The ovary is innervated by the vagus nerve (Burden et al., 1983). In the present study, the effects of right and left cervical vagotomy and abdominal vagotomy on follicular activation and compensatory ovarian hypertrophy in the remaining right or left ovary were compared 15 days after unilateral ovariectomy. Neither right nor left cervical vagotomy affected compensatory ovarian hypertrophy of the right or left ovaries but abdominal vagotomy depressed compensatory ovarian hypertrophy in both the right and left ovaries. Left cervical vagotomy did not inhibit follicular activation, but right cervical vagotomy prevented follicular activation in the right but not left ovary. Also, abdominal vagotomy inhibited follicular activation in the right but not the left ovary. In animals with both ovaries which were subjected to the left or right cervical vagotomy or abdominal vagotomy follicular counts in both right and left ovaries were similar. Collectively, these data indicate that the vagus nerve participates in follicular activation after unilateral ovariectomy. The data also indicate that the right ovary is more dependent on vagal influences for follicular activation than the left ovary.

Effects of abdominal vagotomy on serum LH concentrations in female rats.

Vagotomy on the morning of pro-oestrus did not prevent the pro-oestrous LH surge and rats became oestrous on the following day. However, vagotomized rats then exhibited a period of acyclicity which lasted for 20.4 +/- 1.3 (s.e.m.) days. Food intake and body weight also declined after vagotomy. During the first week after vagotomy, afternoon LH surges generally did not occur, a pattern which was similar in animals pair fed with vagotomized rats. However, pair-fed rats showed oestrous cycles while vagotomized rats were acyclic. At 7 days after vagotomy, LH surges were induced by oestradiol benzoate and progesterone treatment of ovariectomized rats. Vagotomy suppressed the post-ovariectomy increase in serum LH at 7 and 21 days after surgery. These results, combined with those of other studies, suggest impairment of LH release in vagotomized rats.

Comparison of pharyngeal aspirate and amniotic fluid surfactant composition.

Amniotic fluid and oropharyngeal aspirate lung maturity profiles obtained simultaneously at delivery in 16 patients are compared. The lecithin/sphingomyelin ratio was greater in oropharyngeal aspirates than in amniotic fluid (p less than 0.02). The percent phosphatidylinositol was greater in oropharyngeal aspirates than in amniotic fluid (p less than 0.03). The mean differences between percent phosphatidylglycerol were not significant. These findings were uninfluenced by the time interval between amniotic fluid and oropharyngeal sampling, gestational age, or neonatal weight. These data could explain the lack of sensitivity of the amniotic fluid lung maturity profile.

Coping with domestic violence: social support and psychological health among battered women.

This study suggests a conceptual framework for examining the impact of stress (i.e., level of violence), personal resources, social support, institutional responsiveness, and coping upon the psychological health (i.e., depression, mastery, and self-esteem) of battered women. Respondents were 60 women who had sought assistance from a shelter for battered women. Results indicated that increased levels of violence, minimal personal resources, lack of institutional and informal social support, and greater avoidant coping styles were related to lowered self-esteem and more severe depressive symptoms. Exploratory analyses suggested that stress (i.e., level of violence) and personal resources may have indirect effects upon functioning through their impact on coping responses and the availability of social support. In particular, women who had fewer social contacts unaccompanied by their partner were less likely to receive supportive responses from friends. Implications for research and practice are discussed.

Abdominal vagotomy does not activate the corpus luteum in rats.

Rats were vagotomized at proestrus and 4 days later serum prolactin and progesterone were determined by radioimmunoassay. The histology of the ovaries and the activity of ovarian delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) were also studied. There was no difference between hormone values in sham and vagotomized rats 4 days after surgery. In addition, the ovarian histology and activity of 3 beta-HSD were similar in both sham and vagotomized animals. We conclude that vagotomy at proestrus does not interrupt estrous cycles by activating the corpus luteum.

Effect of vagotomy on postcastration gonadotropin secretion in male rats.

The postcastration increase in gonadotropins was studied in intact and vagotomized male rats. Rats underwent vagotomy or sham surgery immediately prior to castration. In the first experiment, rats were bled before castration and at 1, 2, 4, and 7 days after castration. Serum LH and FSH were significantly lower in vagotomized rats 1 day after castration. On days 2, 4, and 7 postcastration, serum gonadotropin levels were generally not different among experimental groups. In a second experiment, rats were decapitated at 12 or 24 hr after surgery and castration. Trunk blood was collected for assay of LH. Vagotomy had no effect on LH levels at 12 hr postcastration, but, at 24 hr postcastration, vagotomized rats had significantly lower serum LH than did sham-operated rats. These experiments indicate that vagotomy has a transient suppressive effect on gonadotropin release following castration. Such observations support the hypothesis that the vagus nerve may play a modulatory role in gonadotropin secretion.

Depletion of tuberoinfundibular dopamine does not restore gonadotropin secretion in ovariectomized hyperprolactinemic rats.

The effect of depleting tuberoinfundibular dopamine (TIDA) on gonadotropin secretion was studied in rats made hyperprolactinemic by implantation of the prolactin and growth hormone secreting Furth MtTW15 tumor. Implants of the pituitary tumor prevented gonadotropin release in response to castration. Daily injection of 100 mg dl-alpha-methyl-para-tyrosine/kg bw which reduced TIDA levels in tumor bearing rats more than 90% did not restore gonadotropin release. It seems likely that the increased activity of the TIDA system does not mediate the suppression of gonadotropins during chronic hyperprolactinemia.

Evidence of prolactin short loop feedback in the postpartum lactating rat.

Serum prolactin was studied in lactating and nonlactating rats after restraint stress, chronic estradiol benzoate treatment, and acute L-tryptophan treatment. As expected, these treatments evoked increases in serum prolactin in nonlactating rats. In lactating rats these treatments did not increase basal serum prolactin when litters were removed for 4 hr. Daily estradiol benzoate treatment increased pituitary gland prolactin content after 14 days, but there was no effect on basal serum prolactin. Daily estradiol treatment did not augment prolactin release in response to 30 min of suckling. It is suggested that the short loop feedback by prolactin (i.e., prolactin inhibiting its own secretion) makes the lactating rat refractory to these stimuli of prolactin secretion.

Chronic hyperprolactinemia depletes hypothalamic dopamine concentrations in male rats.

The tuberoinfundibular dopamine (TIDA) system appears to tonically inhibit pituitary prolactin secretion while moderate elevations in serum prolactin levels, in turn, augment the turnover rate of dopamine (DA) without affecting the steady state concentrations of DA in the TIDA neurons (1-5). The present study demonstrates that chronic elevations in serum prolactin, to greater than 2,000 ng/ml, induced by the prolactin secreting MtTW15 tumor, decreased DA concentrations by 47% in the median eminence-arcuate nucleus (ME-ARC) region, by 43% in the medial basal hypothalamus (MBH) and 14% in the preoptic area-anterior hypothalamic region (POA-AH) without influencing the norepinephrine levels in these regions. Thus, chronic stimulation of hypothalamic DA neurons by prolactin may lead to depletion of DA concentrations and this may be an important factor in the reduced DA levels observed in hyperprolactinemia of senescent rats or that produced by chronic estrogen treatment.

A light and electron microscopic study of the human ovarian ligament.

The structure of the human ovarian ligament was studied with light and electron microscopy, with emphasis on neural components. The ligament is primarily composed of smooth muscle arranged in an outer oblique and an inner longitudinal layer. The smooth muscle cells are connected by two types of intercellular junctional complexes, close contacts and intermediate junctions. The intercellular junctions may serve to coordinate smooth muscle activity and synchronize contractions of the ligament. Nerves are abundant and accompany the vascular supply. Specialized encapsulated neural structures previously reported were not observed. Acetylcholinesterase-positive nerves are more numerous than adrenergic nerves. Both types of nerves are associated with vascular smooth muscle. We conclude that these nerves either traverse the ligament or terminate in the ligament and are vasomotor.