Hagfish natriuretic peptide changes urine flow rates and vascular tensions in a hagfish.

Since the first report of their natriuretic effect on mammalian kidneys the relative influences of natriuretic peptides (NPs) on volume and salt regulation in vertebrates have been debated. As marine osmoconformers, with plasma ionic concentrations similar to seawater, the actions of NPs on hagfishes may provide information on their primordial role. A synthetic natriuretic peptide derived from Eptatretus burgeri (hNP) increased urine production rates in E. cirrhatus at 3x10(-8) M. It also contracted afferent branchial and segmental arteries at low concentrations (1x10(-10) M) and relaxed them at 3x10(-8) M. Thus, hNP has a renal effect and at higher concentrations causes vascular relaxation suggesting a role in volume regulation and the prevention of cardiac overloading. Rat ANP (rANP) stimulated sodium efflux from both isolated, perfused gill pouches and the whole animal. rANP also reduced subcutaneous sinus haematocrit relative to that in the ventral aorta, which is consistent with a vasodilatory role.

Glycyl-L-glutamine injected centrally suppresses alcohol drinking in P rats.

Recent reports show that central beta-endorphin (1-31) injection augments the volitional intake of alcohol. Correspondingly, alcohol drinking stimulates beta-endorphin (1-31) release from the hypothalamus of the rat. Glycyl-l-glutamine (Gly-Gln) is produced in beta-endorphin-containing neurons and is co-released with beta-endorphin(1-31) and other processing products. Because Gly-Gln is apparently an endogenous antagonist of beta-endorphin(1-31) in several systems, the present study was designed to investigate the hypothesis that Gly-Gln injected i.c.v. would alter voluntary alcohol drinking in the genetic, high-alcohol-preferring P rat. After a guide tube was implanted stereotaxically above the lateral cerebral ventricle, the rats were offered 3-30% alcohol over 10 days, and then given their maximally preferred concentration of alcohol in the presence of water for the remainder of the experiment. Gly-Gln or artificial cerebrospinal fluid (CSF) vehicle then was injected i.c.v. in a dose of 10 or 100 nmol for 3 consecutive days, which was followed by a 7-day postinjection interval. Gly-Gln suppressed significantly the intakes of alcohol in terms of both g/kg and proportion to total fluid. During the postinjection days, alcohol drinking continued to be suppressed, whereas neither the daily intakes of food or water nor the body weights of the rats were changed. The present results are consistent with the concept of a functional antagonism by Gly-Gln of the role of beta-endorphin(1-31) in mediating certain central functions. These results demonstrate that alcohol consumption is suppressed by the direct intracerebral application of this unique peptide.

Prostaglandins and hypothalamic neurotransmitter receptors involved in hyperthermia: a critical evaluation.

The role of a prostaglandin of the E series (PGE) in the hypothalamic mechanisms underlying a fever continues to be controversial. This paper reviews the historical literature and current findings on the central action of the PGEs on body temperature (Tb). New experiments were undertaken to examine the local effect of muscarinic, nicotinic, serotonergic, alpha-adrenergic, or beta-adrenergic receptor antagonists at hypothalamic sites where PGE1 caused a rise in Tb of the primate. Guide tubes for microinjection were implanted stereotaxically above sites in and around the anterior hypothalamic, preoptic area (AH/POA) of male Macaque monkeys. Following postoperative recovery, 30-100 ng of PGE1 was micro-injected unilaterally in a volume of 1.0-1.5 microliter at sites in the AH/POA to evoke a rise in Tb, and once identified, pretreated with a receptor antagonist. PGE1 hyperthermia was significantly reduced by microinjections of the muscarinic and nicotinic antagonists, atropine, or mecamylamine, at PGE1 reactive sites in the AH/POA. The serotonergic antagonist, methysergide, injected at PGE1 sensitive sites in the ventromedial hypothalamus also attenuated the rise in Tb. However, the 5-HT reuptake blocker, fluoxetine, and the beta-adrenergic receptor antagonist, propranolol, injected in the AH/POA failed to alter the PGE1 hyperthermia. In contrast, the alpha-adrenergic antagonist, phentolamine, potentiated the increase in Tb at all PGE1 reactive sites in the hypothalamus. An updated model is presented to explain how the concurrent actions of aminergic neurotransmitters acting on their respective receptors in the hypothalamus can interact with a PGE to elicit hyperthermia. Finally, an evaluation of the current literature including recent findings on macrophage inflammatory protein (MIP-1) supports the conclusion that a PGE in the brain is neither an obligatory nor essential factor for the expression of a pyrogen fever.

Anatomical distribution of brainstem sites where PGE1 induces hyperthermia in macaque species.

The neuroanatomical distribution of sites in the diencephalon and mesencephalon within which a prostaglandin (PG) of the E series elicits hyperthermia was characterized in Macaca mulatta and Macaca nemestrina. In 420 experiments undertaken in 13 animals, 225 loci were examined for their reactivity to PGE1 microinjected in a dose of 30 or 100 ng given in a volume of 1.0-1.5 microL. The regions of the brainstem for injection extended rostrally from the thermosensitive cells of the anterior hypothalamic, preoptic area (AH/POA) to the caudal border of the mesencephalon. Colonic and skin temperatures of the monkeys were measured continuously by thermistor probes. A hyperthermic response of > or = 0.5 degrees C and a latency of < or = 45 min was evoked by PGE1 within sites located primarily in the AH/POA. When PGE1 was microinjected at loci located caudal to the AH/POA, the elevation in body temperature (Tb) not only was less intense but rose at a slower rate. A higher concentration of PGE1 in these caudal regions was required to induce hyperthermia comparable with that elicited at loci within the AH/POA. In a second series of experiments either 1.0-5.0 micrograms 5-hydroxytryptamine (serotonin) or a concentration of 10(8) organisms/mL of Escherichia coli was microinjected at PGE1-reactive sites. A close anatomical concordance within the AH/POA of the animal was found in terms of the temporal characteristics and magnitude of the hyperthermia evoked by the indoleamine or lipopolysaccharide. The present results coincide with the reported neuroanatomical distribution of sites in the diencephalon and mesencephalon of other species in which PGE1 causes hyperthermia. Furthermore, these findings support the concept that the local neuronal mechanism of action of a pyrogen in the brainstem of the primate may involve phasic changes in the endogenous activity of both the serotonergic pathway and cyclo-oxygenase system in the AH/POA. In turn, their commonality of action suggests a functional similarity in their effect of shifting the set point for Tb.

A comparison of ovulation suppression and ovulation stimulation in the treatment of endometriosis-associated infertility.

This study compares ovulation stimulation or suppression with the pregnancy rate among infertile couples with endometriosis. The design is a nonrandomized, prospective, multicentered cohort analytic study. Two hundred and ninety-seven couples with laparoscopy-proven endometriosis were analyzed: 68 received no therapy, 42 received clomiphene and 74 received danazol. Forty patients (22%) conceived and pregnancy rates were similar in each treatment group. The relative likelihood of pregnancy associated with clomiphene was 2.9 (95% confidence limits 1.2-7.1); the relative likelihood of pregnancy with danazol was 1.02 (95% confidence limits 0.5-2.3). This study suggests that pregnancy rates during clomiphene treatment could be superior to expectant therapy, while pregnancy rate after danazol is similar to no treatment.

Identifying the presence of antibodies against endometrial antigens. A preliminary study.

Serum and peritoneal fluid from women with and without evidence of endometriosis were tested for the presence of antibodies against endometrial tissue antigens with Western blot analysis. Serum antibodies against endometrial cytosolic antigens of molecular weight 45, 52, 58, 62 and 66 kd were present in samples obtained from women both with and without endometriosis. The patients with endometriosis had serum antibodies against 34-kd endometrial cytosolic antigen, which was not present in serum from fertile women without endometriosis. The peritoneal fluid from patients with endometriosis also reacted with 34-kd endometrial antigen but not the peritoneal fluid from control fertile women. There was no difference in the antigens detected with serum antibody when endometrium from fertile women without evidence of endometriosis and from women with endometriosis was used as a source of antigen. The presence of serum antibody against 34-kd endometrial antigen is specific to endometriosis. However, this antigen is expressed by endometrium of women both with or without endometriosis. Isolation and identification of this antigen may lead to development of a noninvasive aid for the diagnosis of endometriosis.

Effects of central alpha-MSH injections on performance in a cued discrimination task.

Alpha-MSH has been implicated in changing attention behavior following peripheral injections, but no brain sites were studied. In the present report, alpha-MSH was injected directly into specific sites in the medial anterior hypothalamic/preoptic area (MAHPOA) while measuring performance in a visually cued discrimination task. Alpha-MSH injections resulted in reduced errors, indicated by decreased responding during noncued intervals, but no change in responding to correct cues. The improved error rate was consistent with attentional changes in a variety of paradigms. Attentional and motivational parameters were differentiated. The injected alpha-MSH appears to act on an inhibitory component of an attentional mechanism.

Disparate effect of tamoxifen in rats with experimentally induced endometriosis.

The effect of tamoxifen on the growth of endometrial implants was examined in rats with experimentally induced endometriosis. Administration of tamoxifen (1 mg/kg x day) for 60 days completely regressed the endometrial implants. When tamoxifen treatment was withdrawn, recurrence of endometrial implants was observed. Ectopic endometrial implants regressed completely 2 months after ovariectomy in rats with experimentally induced endometriosis. Tamoxifen administration (1 mg/kg x day) for 60 days to ovariectomized rats with regressed implants led to complete recurrence of ectopic endometrial implants. In ovariectomized rats administration of tamoxifen antagonized estradiol-enhanced thymidine incorporation into uterine DNA, but tamoxifen per se stimulated thymidine incorporation. This indicates the agonist/antagonist nature of tamoxifen. Treatment of rats with tamoxifen blocked the normal estrous cycle. However, serum progesterone levels were higher during tamoxifen treatment in rats with intact ovaries than in ovariectomized rats. When ovariectomized rats with regressed implants were administered tamoxifen (1 mg/kg x day) and progesterone (10 mg/kg x day) for 60 days, recurrence of ectopic endometrial implants was not observed. These findings suggest that tamoxifen is effective in regressing endometrial implants in rats with experimentally induced endometriosis, and ovarian progesterone may have a facilitatory effect.

The rat as an animal model for endometriosis to examine recurrence of ectopic endometrial tissue after regression.

The effects of pregnancy and ovariectomy on the growth of endometrial implants were examined in rats with experimentally induced endometriosis. Ectopic implants regressed completely after ovariectomy and we were unable to detect any viable endometrial cells in histological examination of the implant sites. Administration of 17 beta-estradiol cypionate to ovariectomized rats with regressed endometrial implants led to recurrence of the regressed implants. Animals with experimentally induced endometriosis were fertile and the number of embryos on day 10 of pregnancy was not different from the control group. Ectopic implants which regressed during pregnancy recurred 1 month after parturition. It is concluded that endometrial cells may survive at the implanted site even after apparent complete morphological regression, which has the potential to grow into an implant.

Treatment-dependent and treatment-independent pregnancy among women with periadnexal adhesions.

In an attempt to evaluate the efficacy of salpingoovariolysis we studied 147 women who were found to have periadnexal adhesions on laparoscopic examination. Among these women, 69 were treated by laparotomy and salpingoovariolysis and 78 were not treated. There was no significant difference between the degree of adhesions in the treated group and in the nontreated group. With the use of life table analysis, the cumulative pregnancy rate at 12 and 24 months follow-up was 32% and 45% in the treated group and 11% and 16% in the nontreated group, respectively (p less than 10(-6)). We suggest that although pregnancy might occur in infertile women who have periadnexal adhesions, treatment with salpingoovariolysis is associated with a higher pregnancy rate.

Organization of central hyperthermic mechanisms in helium-cold hypothermic hamsters.

We have investigated the ability of three hyperthermic stimuli (PGE2, 5-HT and ACh) to elicit hyperthermia in the Helium-Cold (He-Cold) hypothermic hamster. Hamsters in these conditions are poikilothermic and will passively follow room temperature in a regulated cold room. Animals were injected centrally at AH/POA sites via an indwelling guide tube at body temperatures maintained between 9-12 degrees C. Active sites in the AH/POA were determined prior to the experiment by PGE2 injection. PGE2 injection at an effective AH/POA site immediately reversed the anesthetic induced hypothermia in warm air. Hamsters were induced into hypothermia by the He-Cold induction method and body temperatures were maintained in a 9 degrees C cold room. Colonic temperatures were monitored at 5 minute intervals by a YSI thermistor probe and telethermometer. Central injections of 5-HT (2 micrograms/microliter) and ACh (50 micrograms/microliter) at effective AH/POA sites evoked significant increases in colonic temperature in He-Cold hamsters. PGE2 injections were not different from saline control injections and did not elicit pronounced temperature changes in these animals. Specific blockade of the 5-HT and ACh temperature increases was demonstrated with specific antagonist injections. The results suggest that the central organization of heat-gain mechanisms in the AH/POA is the same as normothermic animals even at temperatures well below those previously investigated.

Induced rewarming by central stimulation in hypothermic hamsters.

Helium-cold hypothermic hamsters, colonic temperature (Tc) 7 to 11 degrees C, injected with acetylcholine (ACH) at a preoptic-anterior hypothalamic (AHPOA) site responded with a rise in colonic temperature while remaining in a cold environmental chamber. The He-Cold hamster does not thermoregulate at these body temperatures. In contrast to central ACH-elicited responses, the injection of alpha and beta adrenergic drugs into the systemic circulation of the He-Cold hamster did not elicit a rise in colonic temperature. The data describe a different animal model of rewarming than has previously been described that is under pharmacologic control by the experimenter. The use of exogenous neurotransmitter provides the potential to understand the mechanisms of thermoregulation in deep experimental hypothermia.

ACh and 5-HT stimulated thermogenesis at different core temperatures in the He-Cold hypothermic hamster.

Hamsters in deep experimentally induced hypothermia, at body temperatures between 7 degrees C and 11.5 degrees C, were microinjected with 5-HT and ACh at brain sites in the anterior-preoptic area of the hypothalamus (AH/POA). ACh or 5-HT was injected into an AH/POA site at different starting core temperatures in different groups of hypothermic hamsters. Colonic temperatures (Tc) were maintained, following He-Cold induction, in a temperature controlled environmental chamber and measured with a YSI thermister probe and YSI telethermometer. Injections of either 5-HT or ACh at Tc's between 7.0 degrees C and 9.0 degrees C elicited only modest increases in Tc i.e., 0.3 degrees C--0.6 degrees C, respectively. As Tc increased, however, to ranges between 9.1 degrees C--10.0 degrees C and in different animals to greater than 10 degrees C both ACh and 5-HT at the same sites elicited significant increases in Tc, 1.5 degrees C for 5-HT and 2.2 degrees C for ACh compared to saline injections. These data suggest that at the lowest Tc's we are observing a "cold block" of temperature sensitive sites in the AH/POA. Increasing the starting Tc beyond 9.0 degrees C however, evokes significant increases in heat-gain following AH/POA injection of either ACh or 5-HT. These data are consistent with Myers' observations concerning the organization of heat-gain mechanisms at AH/POA sites. In addition, they suggest that both the afferent limb of the heat-gain circuit (5-HT) and the efferent limb of the circuit (ACh) are functionally impaired when Tc is close to the physiological limit in the He-Cold hypothermic hamster.

Delayed interval delivery in triplet pregnancy: report of a single case and review of the literature.

A case report of delayed delivery of 99 days in a triplet pregnancy is presented. A triplet pregnancy in a single uterus resulted from Pergonal stimulation of ovulation. At 23.5 weeks' gestation, the first triplet delivered after spontaneous rupture of membranes. Ninety-nine days later, the remaining two fetuses were delivered, the second one stillborn after intrauterine death at 37 weeks of gestation, and the third fetus a normal viable female consistent with 37.5 weeks' gestation. This is the longest interval of delayed delivery discovered from a literature review, and the only such instance of triplet pregnancy in a single uterus.

Recovery by push-pull perfusion of neurochemicals released within the cuneate nucleus of the cat by somatosensory stimulation.

The present work describes a combination of techniques for the identification of neurochemicals released within the cuneate nucleus. During electrical stimulation of the superficial radial nerve, the extracellular fluid of the nucleus is continuously sampled by push-pull perfusion. In addition, the population electrical activity of peripheral nerve as well as the activity of cuneate neurons are recorded. Subsequently, the neurochemical content of the sampled fluid is assessed by HPLC analysis. The comparison of sampled fluid content during control (no stimulation) versus stimulation runs indicates that somatosensory stimulation elicits the release of specific neurochemicals within the cuneate nucleus. The possible sources of released neurochemicals are discussed.

The effect of alcohol on dopamine metabolism in the caudate nucleus of an unanesthetized monkey.

Previously it was shown that the acute administration of ethanol to the rat significantly alters the metabolism of the dopamine (DA) in liver but not in brain tissue. To extend this finding to the primate, two push-pull perfusion cannulae were implanted in the regions of the left and right caudate nucleus of a Macaca nemistrina. After 14C-DA was injected into the caudate, the site ws perfused with an artificial CSF and the perfusate analyzed for the major metalolites of DA. Ethanol was then administered in a dose of 6 g/kg by the nasopharyngeal route. The results show that very little alteration occurs in the metabolism of DA during or postethanol intoxication.

ACTH regulation of tissue-CRF.

The influence of the anterior pituitary on tissue CRF was investigated in two sets of experiments using lesioned, hypophysectomized, adrenalectomized donor rats. Donors were injected with 1 or 0.5 anterior pituitary equivalents 3 h before transfer of plasma to recipient animals. Injection of 1 pituitary equivalent significantly reduced levels of corticosterone in recipient rats compared to saline injection at 3 different time intervals following the transfer. In a second series of experiments donor animals received replacement with saline, ACTH, TSH, or PRL at 0, 2 and 4 h following adrenalectomy; transfer of plasma to recipient animals was at 5 h. Of the three hormones injected only ACTH significantly reduced tissue CRF activity in donor animals. Recipients of these donors showed suppressed levels of corticosterone compared to recipient animals whose donors were injected with saline, TSH or PRL. The ACTH dose-response curve indicates that the effective dose for suppression of tissue CRF in donor animals is in the range of 1-10 mU/ml. Results of these experiments clearly show that tissue CRF is inhibited by the anterior pituitary hormone ACTH rather than by elevated levels of corticosterone. These experiments suggest that feedback regulation of tissue CRF release by ACTH may occur in response to prolonged physical stress.

Pituitary function testing in amenorrhea-galactorrhea-hyperprolactinemia.

Fifteen patients, age 16 to 55, presented with amenorrhea-galactorrhea-hyperprolactinemia. Pituitary function was evaluated by bolus injections of insulin, luteinizing hormone-releasing hormone (LHRH), and thyrotropin-releasing hormone (TRH) in 13 and by LHRH and TRH in 2. Responses to growth hormone (GH), thyroid-stimulating hormone (TSH), cortisol (F), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin were measured. GH, TSH, and F responses were normal in most cases. LH responses were decreased (P less than 0.025) in patients with abnormal sellar tomography, whereas FSH responses tended to decrease with elevated prolactin levels. Prolactin responses were absent in five of the seven cases which could be evaluated. The clinical value of such testing appears to be limited to an individualized basis, although some prognosis of ovulatory response to bromocriptine therapy may be obtained from the gonadotropin response.