Function of abnormal corpora lutea in vivo after GnRH-induced ovulation in the anoestrous ewe

Anoestrous Romney Marsh ewes with and without progesterone treatment (+P, -P) were treated with small-dose (250 ng) multiple injections of GnRH at 2-h intervals for 48 h. Animals were slaughtered on Days 4, 5, 7 and 11 after the end of GnRH treatment and luteal function was assessed by the measurement of daily plasma progesterone concentrations. In all animals which ovulated (29/32, 91%) peripheral progesterone concentrations rose to 0.5-1.0 ng/ml within 3 days of the end of GnRH treatment. In 7/7 (100%) +P animals and 5/22 (23%) -P animals, progesterone concentrations continued to rise and were maintained at levels greater than 1.5 ng/ml until slaughter. In the remaining -P animals, plasma progesterone concentrations declined to reach basal levels by Day 5. Corpora lutea recovered from these animals showed signs of premature regression on Day 5 and were fully regressed by Day 7. Progesterone priming delayed the occurrence of the LH surge which occurred 39.1 +/- 3.6 h after the end of GnRH treatment in the +P animals compared to 20.2 +/- 1.74 h (P less than 0.001) in the -P animals in which luteal function was abnormal and 22.4 +/- 4.35 h in the -P animals in which luteal function was normal. These results show that abnormal luteal function occurs in the majority of GnRH-treated ewes in the absence of progesterone pretreatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of estradiol on the cell kinetics in the uterine and cervical epithelium of neonatal mice.

The effect of estradiol-17beta on the length of the various phases of the cell cycle was studied in the neonatal mouse uterine, and cervical epithelium. A double labelling method was used, and in addition labelled mitoses were counted. In the uterus proper, estradiol shortens the length of the total cell cycle. TC, from 17-9 hr to 15-7 hr, and the duration of S phase, Ts from 6-7 to 5-1 hr 6 hr after estradiol treatment. 12 hr after estradiol treatment, TC is shortened to 7-4 hr and Ts to 4-5 hr. The shortening of TC at 12 hr is manily due to an effect on TG1, which is shortened from 8-55 hr in untreated animals to 1-8 hr in estradiol treated animals. The TC of cervix epithelium cells in untreated animals was found to be 21-8 hr. After treating the mice for 6 hr with estradiol the tc was now increased to 47 hr and further to 61-2 hr following 12 hr treatment with the hormone. Ts increases from 8-3 hr to 15-2 hr following 6 hr estradiol treatment, and to 15-4 hr after 12 hr treatment. The effect is most pronounced in TG1, which is lengthened from 10-95 hr in untreated animals to 28-1 hr and 43 hr, respectively, in animals treated for either 6 or 12 hr with estradiol.     

Long-term isoprenaline administration produces an increase in capillarity in the soleus muscle of the rat

The effects of isoprenaline administration (300 micrograms/kg for 5 weeks) on rat soleus muscle capillarity and glycolytic and oxidative capacities were evaluated. The treatment resulted in ventricular hypertrophy. The activities of lactic dehydrogenase, pyruvate kinase, citrate synthase, and cytochrome c oxidase in soleus muscle homogenates were not different between control and isoprenaline-injected animals. Capillaries were visualized in muscle cross sections treated to demonstrate ATPase activity after acid preincubation. Capillary density was higher in the experimental (873 +/- 38 capillaries/mm2) than in the control (713 +/- 33 capillaries/mm2) animals. Capillary to fiber ratio was also higher in the experimental (2.47 +/- 0.10) than in control (2.09 +/- 0.08) animals, but fiber cross-sectional area was not changed by the treatment (2836 +/- 87 microns2 in controls and 2951 +/- 136 microns2 in experimental). A plot of capillary to fiber ratio vs. fiber cross-sectional area showed that at a given fiber cross-sectional area the value of capillary to fiber ratio of the treated animals was higher than that of the controls. This indicates that treatment resulted in the proliferation of microvessels. The results suggest that prolonged beta-adrenergic stimulation results in the development of new capillaries but that this is not accompanied by increases in the oxidative capacity of the soleus muscle of the rat.     

Endocrine profiles and embryo quality in the PMSG-PGF2alpha treated cow

Plasma progesterone and LH concentrations around estrus were determined for both PMSG treated (experimental animals) and non-treated (control animals) dairy cows and heifers of the Holstein Friesian and Jersey breeds, and these hormone profiles were related to the embryo quality. Most experimental animals experienced an increase in progesterone concentrations following PMSG treatment and an abrupt decrease to values below 3 nmol/l after PG injection. The mean (+/-SE) intervals from prostaglandin treatment to estrus were 46.9+/-1.8 h and 64.5+/-4.8 h for experimental and control animals, respectively. At the onset of heat the progesterone concentration in experimental animals with optimal embryo quality (group I) was significantly lower (p<0.01) than in experimental animals which yielded unfertilized eggs (group II) (1.2+/-0.1 versus 3.9+/-0.8 nmol/l) and significantly higher than the level in the control group (0.6+/-0.1 nmol/l). Following estrus the progesterone profiles in all 3 groups were studied and the length of the superovulatory cycle was measured to 26.0+/-4.8 days. The preovulatory LH surge occurred sooner after prostaglandin injection in experimental (41 h) than in control animals (65 h). The LH surge in group I occurred within a narrow range and reached a higher average level than group II (24.2+/-2.2 ng/ml and 16.3+/-3.7 ng/ml, respectively). The control group attained an even higher LH surge (31.8+/-8.8 ng/ml) than did the experimental animals. The data presented in this experiment indicate that plasma levels of progesterone and LH in PMSG-PGF(2)alpha treated animals are related to embryo or egg quality.     

Estrogen- and progesterone-dependent secretory changes in the uterus of the sheep.

This study was undertaken to determine the effects of 17 beta-estradiol (E) and progesterone (P) on polypeptide synthesis and release from the uterus of the sheep. Uterine flushings (UF) and endometrium were obtained from ovariectomized untreated animals, ovariectomized animals treated with E (approximately 5-10 pg/ml) for 6 days (6E) and ovariectomized animals primed with E for 6 days then treated with P (approximately 1.5-3 ng/ml), in the continued presence of E, for an additional 6 days (6EP). Endometrium was cultured (24 h) in the presence of 3H-leucine (3H-leu) or 3H-glucosamine (3H-glcN), and newly synthesized and released proteins were detected in culture media by fluorography of 10% SDS gels. The quantity of proteins in UF and radiolabeled proteins in explant culture media did not change between treatment groups (p < 0.05). Qualitative changes in the synthesis and release of proteins were observed depending on the steroid treatment. An M(r) 57,000 protein was present in UF and 3H-leu-labeled culture media obtained from animals treated only with E and an M(r) > 200,000 was present in 3H-leu-labeled culture media of endometrium obtained from 6E and 6EP animals. An M(r) 44,000 protein was present only in UF from 6EP animals but could not be detected in endometrial culture media from animals undergoing this steroid treatment. These data show that the endometrium of the ovariectomized sheep undergoes alterations in secretory protein patterns which depend on the presence of E and P.     

Integrating fasciolosis control in the dry cow management: the effect of closantel treatment on milk production

The liver fluke Fasciola hepatica is a parasite of ruminants with a worldwide distribution and an apparent increasing incidence in EU member states. Effective control in dairy cattle is hampered by the lack of flukicides with a zero-withdrawal time for milk, leaving the dry period as the only time that preventive treatment can be applied. Here, we present the results of a blinded, randomized and placebo-controlled trial on 11 dairy herds (402 animals) exposed to F. hepatica to 1) assess the effect of closantel treatment at dry-off (or 80-42 days before calving in first-calving heifers) on milk production parameters and 2) evaluate if a number of easy-to-use animal parameters is related to the milk production response after treatment. Closantel treatment resulted in a noticeable decrease of anti-F. hepatica antibody levels from 3-6 months after treatment onwards, a higher peak production (1.06 kg) and a slightly higher persistence (9%) of the lactation, resulting in a 305-day milk production increase of 303 kg. No effects of anthelmintic treatment were found on the average protein and fat content of the milk. Milk production responses after treatment were poor in meagre animals and clinically relevant higher milk production responses were observed in first-lactation animals and in cows with a high (0.3-0.5 optical density ratio (ODR)), but not a very high (≥0.5 ODR) F. hepatica ELISA result on a milk sample from the previous lactation. We conclude that in dairy herds exposed to F. hepatica, flukicide treatment at dry-off is a useful strategy to reduce levels of exposure and increase milk production in the subsequent lactation. Moreover, the results suggest that treatment approaches that only target selected animals within a herd can be developed based on easy-to-use parameters.     

TP53 overexpression in radiation-induced osteosarcoma of the rabbit mandible

The objective of this study was to investigate the incidence of overexpression of TP53 (formerly known as p53) in osteosarcomas occurring after treatment of rabbit mandibles with high-dose external-beam radiation. As part of a protocol investigating hyperbaric oxygen treatment for osteoradionecrosis, 102 female New Zealand-White rabbits underwent mandibular radiation treatments with a total dose of 64 Gy in 20 treatment fractions. Twelve animals died during irradiation, leaving 90 animals at risk for tumor development. These animals were divided into one control group and 12 other groups each treated with different schedules of postirradiation hyperbaric oxygen. All animals were sacrificed after the hyperbaric oxygen treatment, approximately 8 months after completion of irradiation. Seventeen of the 90 animals that survived after irradiation developed high-grade osteosarcomas, for a 19% incidence of malignancy. Tumor sizes ranged from 1-4 cm. Immunohistochemistry staining of the 17 tumors detected a 59% overall incidence of TP53 overexpression. There was no correlation between the intensity of hyperbaric oxygen treatment and development of osteosarcoma. The high incidence and short interval of development of osteosarcoma suggest that the study animals may have had a genetic predisposition to radiation-induced osteosarcoma. Additionally, our data provide further evidence that TP53 mutations may play an important role in radiation-induced osteosarcoma.     

The effect of estrogen and progesterone on structural changes in the uterine glandular epithelium of the ovariectomized sheep.

The development of epithelial cells of the uterine glands of ovariectomized sheep in response to estradiol-17 beta (E) and progesterone (P) was studied using light and electron microscopy. Animals that had been ovariectomized for six weeks were placed in one of three experimental treatment groups. Group I animals (untreated controls) received no steroid treatment. Group II animals (E alone) received one 4-cm E implant (E approximately 5-10 pg/ml) and their uteri were removed after 2, 4, or 6 days. Group III animals (E-primed, P-treated) received an E implant (E approximately 5-10 pg/ml) for 6 days and then were treated with six 13-cm P implants (P approximately 1.5-3 ng/ml), in the continued presence of E, for 2, 4 or 6 days. Six weeks after ovariectomy the epithelial cells of the uterine glands were low cuboidal and morphologically appeared to be synthetically inactive. Following 2 days of E treatment the epithelial cells had significantly increased in cell height, and protein-synthesizing organelles were well developed. Maturation of the secretory apparatus continued throughout E treatment. The Golgi complex and rough endoplasmic reticulum (RER) were abundant. Lysosomal-like granules and granules of varying electron density were present in the cytoplasm. The chronic administration of P to E-primed animals did not result in any further increase in cell height. Elongated mitochondria, a cup-shaped Golgi apparatus, extensive apical microvilli, and irregularly shaped membranous profiles in the supranuclear cytoplasm characterized these uterine epithelial cells. Lysosomal-like granules, small vesicles, and scattered patches of glycogen were seen in the cytoplasm. These data show that the uterine epithelial cells of the ovariectomized sheep undergo morphological alterations in protein-synthesizing organelles and apical specializations that depend on the presence of E and P.     

Frequency of the stages in the cycle of the seminiferous epithelium in the rat

This study determined the optimum number of tubules to be counted per testis cross section, and the number of animals per treatment group, when changes in stage frequencies in the cycle of the seminiferous epithelium are criteria for assessing effects of treatment on spermatogenesis. A data base of 9,672 observed and staged tubules was collected from testicular cross sections of 15 Sprague-Dawley rats. A significant variation between animals was found for the frequencies of Stages I, II, IV, VI, VIII, and XIII. Computer simulation was used to randomly select different combinations of animal and tubule numbers from the observed data. Stage frequency means from each simulation experiment were compared statistically to observed mean frequencies. A model that used data from all 14 stages was analyzed. The following conclusions were made: a) a minimum of 200 tubule cross sections/testis is recommended for estimating stage frequencies; b) for a fixed number of tubules scored, the number of animals sampled is more important than the number of tubules per animal in reducing variance; c) to detect a difference of 2 standard deviations from the mean with a 2% error rate and examining 200 tubules/testis, at least 12 animals must be used per group when assessing all 14 stages; d) when individual stages are examined using 10 animals per group, only Stage VII has 80% or greater power of test (alpha = 0.05) to detect a frequency difference; e) pooling stages into 3-4 groups is recommended to improve the power of detecting a treatment difference.     

The restraint stress-induced decrease of the nocturnal prolactin surge and the physiology of pseudopregnancy and pregnancy in the rat

Experiments were performed to determine whether the restraint stress-induced decrease of the nocturnal prolactin (PRL) surge affected the length of pseudopregnancy (PSP) and/or the outcome of pregnancy in rats. Vaginal cycles were monitored daily and animals were electro-mechanically cervically stimulated on the morning of metestrus to induce PSP. Animals were restraint stressed by tying the hind legs together with plastic coated bell wire beginning on day 1 of PSP from 0100-0700h with reapplication of stress at 0400h for 6-9 days and then blood sampled for PRL and progesterone plasma levels. Restraint stress significantly decreased plasma PRL (P less than 0.001) and progesterone (P less than 0.05) levels. The length of PSP was significantly decreased (P less than 0.01) for restraint animals and for control animals that were blood sampled compared to control animals that were not sampled. In the pregnancy experiment, animals were mated upon arrival into the laboratory and assigned to one of four groups. For the restraint group, stress was initiated on day 1 of pregnancy as indicated by the presence of sperm in the vaginal lavage. Animals were stressed for 6-9 days for 6 hours during the nocturnal PRL surge as described above. One control group had no treatment; a second control group was sampled only, and a third control group was injected daily with pimozide, a dopamine antagonist, and stressed for 6-9 days. The group which received no treatment had significantly greater (P less than 0.05) incidence of successful pregnancy compared to the other 3 groups; there were no differences (P greater than 0.05) between the sampled, restraint and restraint + pimozide groups in the incidence of successful pregnancy. We conclude that restraint stress during the nocturnal PRL surge minimally affects the length of PSP and that the effect of stress on the outcome of pregnancy is not due to the decrease in nocturnal PRL surge.     

Studies on the anti-tumor efficacy of systemically administered recombinant tumor necrosis factor against several murine tumors in vivo

The anti-tumor activity of recombinant human tumor necrosis factor (rHTNF) was examined against four newly induced murine sarcomas (MCA-101, -102, -105, and -106) and a murine adenocarcinoma (MCA-38) transplanted s.c. into C57BL/6 mice. The serum half-life after a single i.v. injection of rHTNF was determined to be 30 +/- 2 min. Tumor-bearing mice were more susceptible to the toxic side effects of rHTNF than were normal mice. Forty-eight percent (41/86) of tumor bearing animals that received 10 micrograms rHTNF died within 48 hr after treatment compared with no deaths in 28 normal animals receiving this dose. Treatment of mice bearing either the MCA-101, -102, -105, or -106 sarcoma or the MCA-38 adenocarcinoma with rHTNF resulted in a marked necrosis of the central portion of each tumor within 24 hr. Animals bearing the weakly immunogenic tumors MCA-105, -106, and -38 experienced a reduction in average tumor area of 47% +/- 5, 46% +/- 6, and 37% +/- 11, respectively, by 3 to 4 days after treatment with rHTNF compared with pre-treatment values (p less than 0.001); increases of 79% +/- 11, 74% +/- 10, and 41% +/- 6 were seen in excipient-treated control animals over the same period. In contrast, animals bearing the non-immunogenic tumors MCA-101 and -102 experienced little if any decrease in tumor area at the doses of rHTNF used. rHTNF failed to mediate cures in animals bearing MCA-38, -101, or -102. In contrast, 67 and 28% of animals bearing MCA-105 and -106, respectively, which received 6 to 10 micrograms rHTNF were cured. Likewise, animals bearing MCA-105 and -106 sarcomas treated with 6 to 10 micrograms rHTNF had significantly increased survival compared with excipient-treated control animals. In contrast, no significant difference in mean survival was observed between excipient and rHTNF treated animals bearing MCA-38, -101, or -102. Histologically, the necrotic response of immunogenic MCA-106 and non-immunogenic MCA-102 tumors to systemically administered rHTNF was very similar. These two tumors differed morphologically, however, by the greater degree of chronic inflammation that was present at the periphery of the MCA-106 tumor in comparison with the MCA-102. By 72 hr after rHTNF administration, the sites of regressed MCA-106 tumors were replaced by a heterogeneous population of inflammatory cells and tumor cell "ghosts".(ABSTRACT TRUNCATED AT 400 WORDS)     

The effects of melatonin, N-acetylserotonin, and 6-hydroxymelatonin on the ultrastructure of the pinealocytes of the Syrian hamster (Mesocricetus auratus)

OBJECTIVES: The aim of this study was to examine the effects of melatonin as well as of its precursor (N-acetylserotonin) and metabolite (6-hydroxymelatonin) on the ultrastructure of the pinealocytes of the Syrian hamster. MATERIAL AND METHODS: The pineal glands of 2-month-old male Syrian hamsters were examined. The animals were divided into the following groups of four animals each: group 1 - melatonin treatment; group 2 - N-acetylserotonin treatment; group 3 - 6-hydroxymelatonin treatment (all substances given subcutaneously at doses of 25 microg per animal between 16.00 and 17.00 h daily for seven weeks). Group 4 was given solvent treatment only and served as controls. The animals were killed by decapitation between 09:00 and 10.00 h. Routine electron microscopical techniques were used to obtain quantitative data on pinealocyte ultrastructure. RESULTS: Melatonin administration did not influence the size of the hamster pinealocytes, whereas administration of N-acetylserotonin and 6-hydroxymelatonin caused a significant reduction in cell size in comparison to the melatonin-treated and control groups. There were changes in the relative volumes of the mitochondria, Golgi apparatus and lysosomes in the pinealocytes of the studied groups, while the volumes of granular endoplasmic reticulum and lipid droplets were unchanged. The dense-core vesicles were more numerous in the pinealocytes of the melatonin and 6-hydroxymelatonin-treated groups in comparison to those of animals treated with N-acetylserotonin or the controls. CONCLUSIONS: The changes observed in the ultrastructure of hamster pinealocytes indicate that administration of melatonin as well as of its precursor or metabolite influences the morphology of these cells and also, perhaps, their secretory activity.     

Mannitol induces selective astroglial death in the CA1 region of the rat hippocampus following status epilepticus

In the present study, we addressed the question of whether treatment with mannitol, an osmotic diuretic, affects astrogliovascular responses to status epilepticus (SE). In saline-treated animals, astrocytes exhibited reactive astrogliosis in the CA1-3 regions 2-4 days after SE. In the mannitol-treated animals, a large astroglial empty zone was observed in the CA1 region 2 days after SE. This astroglial loss was unrelated to vasogenic edema formation. There was no difference in SE-induced neuronal loss between saline- and mannitol-treated animals. Furthermore, mannitol treatment did not affect astroglial loss and vasogenic edema formation in the dentate gyrus and the piriform cortex. These findings suggest that mannitol treatment induces selective astroglial loss in the CA1 region independent of vasogenic edema formation following SE. These findings support the hypothesis that the susceptibility of astrocytes to SE is most likely due to the distinctive heterogeneity of astrocytes independent of hemodynamics. [BMB Reports 2015; 48(9): 507-512]     

Cellular proliferation in the anterior pituitary of the rat during the postnatal period

Summary Cellular proliferation in the anterior pituitary of 2-, 8-, 15- and 30-day-old rats was examined by injection of bromodeoxyuridine 1 h before autopsy. Bromodeoxyuridine incorporated into DNA was detected immunohistochemically by use of a monoclonal antibody. The highest rate of cell proliferation was found in 2-day-old animals; it decreased thereafter during the postnatal period. Possible toxic effects of colchicine on cellular proliferation were examined. Colchicine treatment (10 mg/kg in 8- and 30-day-old animals) significantly decreased the number of bromodeoxyuridine-labelled cells/mm² in 8-day-old rats. Some sections were doubly immunostained for bromodeoxyuridine and various pituitary hormones. The proportion of doubly-immunostained cells to all proliferating cells was generally low, ranging from 23% at 2 days to 32% at 30 days of age.On leave from the Department of Human Anatomy and Histology, Faculty of Medicine, University of Salamanca, Salamanca, Spain     

Effects of dichloroacetate in spinal stroke in the rabbit

High levels of brain lactate may contribute to cellular death and dysfunction in acute cerebral ischemia. Although sodium dichloroacetate (DCA) has been shown to lower brain lactate in incomplete cerebral ischemia, functional outcome has not been assessed with DCA. We examined the effects of DCA treatment on functional neurologic outcome using a previously developed model for "spinal stroke" in the rabbit. Thirty male New Zealand white rabbits weighing 1.3-2.8 kg were studied. After anesthesia with 15-40 mg/kg pentobarbital IV, a laparotomy was performed and the aorta exposed. A metal clamp was placed on the aorta just distal to the left renal artery for 20 minutes and then removed. The abdominal wound was closed in two layers. Animals then received either 2cc normal saline (n = 15) or 300 mg/kg DCA in 2cc normal saline (n = 15) over 10 minutes. The animals were returned to their cages when awake and were examined at 24 hours, 48 hours, and 72 hours for neurologic assessment. The exams were performed by a blinded examiner who was unaware of the treatment given. A three point ambulatory score (0 = can't walk, 1 = walk but not hop, 2 = hopping) and a two point activity score (0 = inactive, 1 = active) were used. At 24 hours, 67% of the DCA-treated animals were actively moving about compared to only 27% of the controls (P = 0.03; Fisher Exact Test). Ten of fifteen control animals were unable to walk, while only five of fifteen DCA-treated animals were unable to walk (P = 0.07). Sixty percent of the DCA animals were able to hop compared to 27% of controls (P = 0.06). These results suggest that DCA can reduce morbidity from spinal cord ischemia in the rabbit.     

The role of leukotrienes in the late hemodynamic manifestations of group B streptococcal sepsis in piglets

In order to evaluate the role of leukotrienes in group B streptococcal (GBS) sepsis we studied the effect of a leukotriene receptor antagonist, FPL 57231, on the late hemodynamic changes occurring secondary to an infusion of live GBS. Paralyzed, mechanically ventilated piglets received a continuous intravenous infusion of bacteria (5 x 10(7) org/kg/min) while systemic arterial (Psa) and pulmonary artery pressures (Ppa) were measured. To separate the effects of the lipoxygenase products of arachidonic acid from those of the cyclooxygenase by-products, animals in control and treatment groups received indomethacin, a cyclooxygenase blocking agent, 15 min after the infusion of GBS was begun. In addition to GBS and indomethacin, treatment animals received a 30 min infusion of FPL 57231 starting 120 min after the bacterial infusion was begun. All study animals responded to bacteria within 15 min with marked elevation in pulmonary artery pressure (X +/- SD) (12 +/- 3 to 49 +/- 5 mmHg; p less than .01), and a decline in PaO2 (84 +/- 9 to 49 +/- 5 mmHg; p less than .01) and cardiac output (0.29 +/- 0.04 to 0.18 +/- .07 liter/min/kg; p less than .01). These changes were reversed by indomethacin. Subsequent values remained relatively stable until approximately 90 min when a gradual decrease in cardiac output (CO) and PaO2, and an increase in Ppa, and calculated systemic (SVR) and pulmonary (PVR) vascular resistances occurred. After the initial increase in TxB2 and 6-keto-PGF1 alpha, indomethacin treatment resulted in return of these values to baseline with no further increase throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of testosterone on the development of a sexually dimorphic neuromuscular system in ciliary neurotrophic factor receptor knockout mice.

Motoneurons in the spinal nucleus of the bulbocavernosus (SNB) innervate the perineal muscles, bulbocavernosus (BC), and levator ani (LA). Testosterone regulates the survival of SNB motoneurons and BC/LA muscles during perinatal life. Previous findings suggest that effects of testosterone on this system may be mediated by trophic factors-in particular, by a factor acting through the ciliary neurotrophic factor alpha-receptor (CNTFRalpha). To test the role of CNTFRalpha in the response of the developing SNB system to testosterone, CNTFRalpha +/+ and -/- mice were treated with testosterone propionate (TP) or oil during late embryonic development. BC/LA muscle size and SNB motoneuron number were evaluated on the day of birth. Large sex differences in BC and LA muscle size were present in newborn mice of both genotypes, but muscle volumes were reduced in CNTFRalpha -/- animals relative to same-sex, wild-type controls. Prenatal testosterone treatment completely eliminated the sex difference in BC/LA muscle size in wild-type animals, and eliminated the effect of the CNTFRalpha gene deletion on muscle size in males. However, the effect of TP treatment on BC and LA muscle sizes was blunted in CNTFRalpha -/- females. SNB motoneuron number was sexually dimorphic in oil-treated, wild-type mice. In contrast, there was no sex difference in SNB motoneuron number in oil-treated, CNTFRalpha knockout mice. Prenatal treatment with testosterone did not increase SNB motoneuron number in CNTFRalpha -/- mice, but also did not significantly increase SNB motoneuron number in newborn wild-type animals. These findings confirm the absence of a sex difference in SNB motoneuron number in CNTFRalpha -/- mice. Moreover, the CNTFRalpha gene deletion influences perineal muscle development and the response of the perineal muscles to testosterone. Prenatal TP treatment of CNTFRalpha -/- males overcomes the effects of the gene deletion on the BC and LA muscles without a concomitant effect on SNB motoneuron number.     

The chronological relationship between the thickening of smooth muscle, epithelial cell proliferation and myenteric neural denervation in the rat jejunum

The jejunum of rats was treated by serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaC1). The animals were allocated to eight groups of 10 rats each and sacrificed 15, 30, 45, 60 days after BAC treatment. Segments were removed from the jejunum for neuronal counting, measurement of the smooth muscle area and morphokinetic study of the epithelium. There was a significant reduction in neuron number in the myenteric plexus 30 days after BAC treatment, thickening of smooth muscle 15-60 days after BAC treatment, but no change in epithelial cell proliferation in the jejunum at either time.     

Combination therapy with acipimox enhances the effect of growth hormone treatment on linear body growth in the normal and small-for-gestational-age rat

Growth hormone (GH) therapy is often associated with adverse side effects, including impaired insulin sensitivity. GH treatment of children with idiopathic short stature does not lead to an optimized final adult height. It has been demonstrated that FFA reduction induced by pharmacological antilipolysis can stimulate GH secretion per se in both normal subjects and those with GH deficiency. However, to date, no investigation has been undertaken to establish efficacy of combination treatment with GH and FFA regulators on linear body growth. Using a model of maternal undernutrition in the rat to induce growth-restricted offspring, we investigated the hypothesis that combination treatment with GH and FFA regulators can enhance linear body growth above that of GH alone. At postnatal day 28, male offspring of normally nourished mothers (controls) and offspring born with low birth weight [small for gestational age (SGA)] were treated with saline, GH, or GH (5 mg.kg(-1).day(-1)) in combination with acipimox (GH + acipimox, 20 mg.kg(-1).day(-1)) or fenofibrate (GH + fenofibrate, 30 mg.kg(-1).day(-1)) for 40 days. GH plus acipimox treatment significantly enhanced linear body growth in the control and SGA animals above that of GH, as quantified by tibial and total body length. Treatment with GH significantly increased fasting plasma insulin, insulin-to-glucose ratio, and plasma volumes in control and SGA animals but was not significantly different between saline and GH-plus-acipimox-treated animals. GH-induced lipolysis was blocked by GH plus acipimox treatment in both control and SGA animals, concomitant with a significant reduction in fasting plasma FFA and insulin concentrations. This is the first study to show that GH plus acipimox combination therapy, via pharmacological blocking of lipolysis during GH exposure, can significantly enhance the efficacy of GH in linear growth promotion and ameliorate unwanted metabolic side effects.