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PubMed2004

Apolipoprotein E genotype and age at menopause.

We tested the hypothesis that there is a connection between apolipoprotein E (APOE) genotype and age at menopause. A sample of women aged between 50 and 60 years who had reached natural menopause was studied. Survival analysis of data showed a significant relationship between APOE genotype and age at menopause, carriers of the APOE4 allele reaching menopause at an earlier age. Our findings can have a bearing on the question of the evolution of this major human polymorphism and human life history. These findings are also relevant to the question of the connection between reproductive parameters and age-associated diseases.

Age Factors↗

PubMed1993

The chronic intracerebroventricular infusion of interleukin-1 beta alters the activity of the hypothalamic-pituitary-gonadal axis of cycling rats. II. Induction of pseudopregnant-like corpora lutea.

The acute administration of interleukin-1 beta (IL-1 beta) into the brain ventricles of rats has been shown to cause a significant decrease in plasma LH levels, a phenomenon primarily mediated through inhibition of LHRH release. However, there are no studies of the long-term consequences of IL-1 beta injected intracerebroventricularly on the hypothalamic-pituitary-gonadal axis. In particular, we became interested in determining whether IL-1 beta exerts deleterious effects on reproductive parameters, and to what extent they might be caused by a lowering of circulating gonadotropins. In the present experiments, we therefore investigated the effects of the infusion of IL-1 beta to intact cycling female rats and compared them to those observed in rats injected with a potent LHRH antagonist. Although blockade of LHRH receptors caused a modest and delayed inhibition of progesterone secretion, infusion of IL-1 beta (4 ng/h for 4-6 days) was accompanied by persistent and significant increases in plasma P4 levels. In these rats, the PRL release was erratic, with low values during the morning and generally extremely elevated values during the night. The volume of the corpora lutea-I (CL-I) of rats exposed to IL-1 beta, but not to the vehicle or the LHRH antagonist, was significantly increased, and the lutein cells showed extensive hypertrophy. These results indicate that prolonged infusion of IL-1 beta into the brain of cycling rats blocks luteolysis in newly formed CL. These changes were not present in rats injected with the LHRH antagonist, suggesting that they were not primarily related to decreases in gonadotropin secretion. We propose that the high plasma PRL levels may play a role in the changes in ovarian activity which we observed, through other mechanisms, such as sustained increases in adrenal epinephrine and/or glucocorticoids, may also be involved. These findings indicate a novel role for central IL-1 beta in the prevention of luteolysis and the transformation of the CL of the cycle into a CL of pseudopregnancy.

Animals↗

PubMed2003

Dietary composition in restoring reproductive and metabolic physiology in overweight women with polycystic ovary syndrome.

Overweight women with polycystic ovary syndrome (PCOS) were randomized to a high protein (HP; 40% carbohydrate and 30% protein; n = 14) or a low protein (LP; 55% carbohydrate and 15% protein) diet (n = 14). The intervention consisted of 12 wk of energy restriction (approximately 6000 kJ/d), followed by 4 wk of weight maintenance. Pregnancies (two HP and one LP); improvements in menstrual cyclicity, lipid profile, and insulin resistance (as measured by the homeostasis model); and decreases in weight (7.5%) and abdominal fat (12.5%) occurred independently of diet composition. Improvements in menstrual cyclicity were associated with greater decreases in insulin resistance and fasting insulin (P = 0.011). On the LP diet, high density lipoprotein cholesterol decreased 10% during energy restriction (P = 0.008), and the free androgen index increased 44% in weight maintenance stages (P = 0.027). Weight loss leads to improvements in cardiovascular and reproductive parameters potentially mediated by improvements in surrogate measures of insulin resistance. An HP weight loss diet may result in minor differential endocrine and metabolic improvements.

Adult↗

PubMed2003

Inhibin secretion in the golden hamster (Mesocricetus auratus) testis during active and inactive states of spermatogenesis induced by the restriction of photoperiod.

Gonadal function in the male golden hamster (Mesocricetus auratus) was investigated during exposure to a short photoperiod condition. Within 3 weeks of exposure to the short photoperiod condition, FSH and testosterone in the plasma significantly decreased, and subsequently immunoreactive (ir)-inhibin significantly decreased. Testicular contents of ir-inhibin and testosterone, and pituitary contents of LH and FSH also significantly decreased by 3 weeks with regression of weight of testes, epididymis and seminal vesicles and sperm head count. Circulating LH varied but not significantly. Thereafter, all reproductive parameters and secretion of LH, FSH, ir-inhibin and testosterone gradually recovered after 17 weeks of exposure even though animals continued to be subjected to the short photoperiod condition. Plasma concentrations of inhibin B and inhibin pro-alphaC were detectable and were significantly decreased after 15 weeks of exposure to the short photoperiod, but their levels were still detectable. Immunopositive reaction of inhibin alpha and betaB subunits was found in Sertoli cells and Leydig cells in the regressed testes of animals subjected to short photoperiod as was also seen in animals before exposure to the short photoperiod. Although the spermatogenic cycle was suppressed like prepubertal animals, the present study showed that the testicular recovery, so-called refractoriness, is functionally different from the developing stage of immature animals, especially with regard to inhibin secretion. The present results showed that changes in FSH preceded changes in inhibin during the regression and recovery phases, indicating that FSH is a major regulatory factor of inhibin secretion in male golden hamsters. The present study also demonstrated that regressed testes still secrete a small amount of bioactive inhibin during exposure to a short-photoperiod condition.

Animals↗

PubMed2002

The effect of metformin on hirsutism in polycystic ovary syndrome.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is a common reproductive disorder characterised by insulin resistance and often associated with hirsutism. Insulin sensitising agents, such as metformin, improve both the biochemical and reproductive parameters; however, no study has been designed to specifically assess the effect of metformin on hair growth. DESIGN AND PATIENTS: Sixteen women with PCOS and hirsutism were enrolled into a 14 month (two 6 month phases with a 2 month washout) double-blind placebo-controlled cross over study. MEASUREMENTS: Hirsutism was assessed using the Ferriman and Gallwey (F-G) score, patient self-assessment and growth velocity. Weight, height and waist-hip ratio were recorded. Gonadotrophins, androgens, plasma glucose and lipids were also measured. RESULTS: Ten women completed the full 14 month study. There was a significant improvement in hirsutism at the end of the metformin phase compared with placebo: F-G score 15.8+/-1.4 vs 17.5+/-1.2 (P=0.025) and patient self-assessment 2.4+/-0.1 vs 3.3+/-0.3 (P=0.014). Growth velocity, in millimetres per day at the end of each phase also improved (0.67+/-0.17 vs 0.77+/-0.11; P=0.03). There was a non-significant improvement in both sex hormone binding globulin (SHBG) and free androgen index (FAI), although there was a significant difference between baseline and metformin treatment for SHBG (P=0.023) and FAI (P=0.036). Metformin treatment also reduced weight significantly (91.5+/-7.6 vs 94.0+/-9.8 kg; P=0.009) and led to a significant improvement in cycle frequency (0.53+/-0.12 vs 0.35+/-0.08 cycles per month; P=0.008). CONCLUSION: We have demonstrated that metformin treatment in a group of women with PCOS results in a clinically and statistically significant improvement in hair growth compared with placebo.

Body Constitution↗

PubMed1999

Mapping of quantitative trait loci for seminal vesicle mass and litter size to rat chromosome 8.

The spontaneously hypertensive rat (SHR) and the Brown Norway (BN) rat differ significantly in litter size (7.6 versus 4.5 pups). In the HXB and BXH sets of recombinant inbred (RI) strains derived from SHR and BN rats, heritability of litter size and of selected male reproductive parameters such as sperm production, sperm count, sperm morphology and motility, and the mass of the testis, epididymides, and seminal vesicles were estimated and a search was undertaken for quantitative trait loci (QTL) associated with these phenotypes. The mass of seminal vesicles was significantly associated with a QTL near the D8Cebr204S21 marker on chromosome 8 (LOD score = 4.1, P = 0.00001); this QTL was responsible for 46% of the genetic variability of the trait. The same gene marker on chromosome 8 also showed a suggestive association with the litter size. Litter size was significantly correlated with the mass of seminal vesicles (r = 0.58, P = 0.003). These findings indicate that the variability in litter size among RI strains may be due in part to differences in the mass of seminal vesicles and it is possible that both mass of seminal vesicles and litter size are determined by a pleiotropic effect of the same QTL on rat chromosome 8.

Animals↗

PubMed2003

Effect of treatment with the selective oestrogen receptor modulator LY117018-HCl on pituitary sensitivity to GnRH and subsequent ovulation.

The effects of LY117018-HCl (LY; a benzothiophene similar to raloxifene) were examined on various reproductive parameters in female rats. Four-day cyclic rats were treated (10:00 h on dioestrus) with LY (0.01, 0.1, 0.5, 1, 2, 4 or 16 mg kg(-1) p.o.) and assessed for ovulation at oestrus. LY inhibited ovulation at doses as low as 0.5 mg kg(-1), and ovulation did not occur at doses of 4 and 16 mg kg(-1). LY (16 mg kg(-1)) reduced wet uterine mass and LH concentrations at the time of the expected ovulatory surge. Ovulation induced by hCG in pentobarbital-treated rats was not altered by LY treatment, indicating normal ovarian sensitivity to gonadotrophins. LY, however, completely blocked the effects of oestradiol (under either negative or positive feedback modes) on LH secretion in ovariectomized rats. GnRH secretion into hypophyseal portal blood during pro-oestrus was not affected by treatment with LY, whereas the concentrations of serum LH remained reduced. Finally, treatment with LY markedly reduced pituitary sensitivity to GnRH during pro-oestrus, as it completely blocked GnRH-induced LH secretion. These results demonstrate that LY inhibits oestradiol action in the uterus and prevents ovulation in normal cyclic rats. LY-induced inhibition of ovulation is not caused by an alteration of the ovarian response to gonadotrophins or an impairment of GnRH secretion at the hypothalamus, but by a reduction in the sensitivity of gonadotrophs to the stimulatory effects of GnRH during pro-oestrus.

Animals↗

PubMed2002

Lack of parthenogenesis by Amblyomma cajennense (Acari: Ixodidae).

Some reproductive parameters of adult stages of Amblyomma cajennense ticks were studied. The capacity of virgin females to reproduce by parthenogenesis was evaluated, during an experimental infestation, in absence of males, on a horse (Equus cabalus). Ticks were spread either completely free or in limited sites on the body of the animal. The engorged virgin females showed longer feeding periods and lighter body weights than those that had been fertilized. Some of these unmated females produced smaller egg masses, which had no embryonary development. On the other hand, females that had been inseminated produced larger egg masses, with normal embryonary development that led to viable larvae. Under the studied conditions, A. cajennense females did not reproduce by parthenogenesis.

Animals↗

PubMed2002

The terrestrial reptile fauna of the Abrolhos Archipelago: species list and ecological aspects.

We have studied the terrestrial reptile fauna of the Abrolhos Archipelago (a group of five islands located ca. 70 km off the southern coast of the State of Bahia, Brazil) and analyze here some of its ecological aspects such as diet, thermal ecology, activity, and some reproductive parameters. Three lizards comprise the archipelago's terrestrial reptile fauna: Tropidurus torquatus (Tropiduridae), Mabuya agilis (Scincidae), and Hemidactylus mabouia (Gekkonidae). The first two are diurnal and the latter is crepuscular/nocturnal (initiating activity at ca. 17:30). The activity period of T. torquatus extended from 5:30 to 18:30 h. Mean field body temperatures of active T. torquatus, M. agilis, and H. mabouia were, respectively, 34.0 +/- 3.7 degrees C (range 23.8-38.0 degrees C; N = 75), 34.5 +/- 2.2 degrees C (range 30.8-37.0 degrees C; N = 6), and 26.3 +/- 1.1 degrees C (range 24.8-28.0 degrees C; N = 8). The predominant prey items in the diet of T. torquatus were ants, coleopterans, and hemipterans. In the diet of M. agilis, coleopterans were the most frequent prey items. For H. mabouia, the most important dietary items were orthopterans. Clutch size of T. torquatus averaged 4.1 +/- 1.1 (range 2-6; N = 15) and was significantly related to female size (R2 = 0.618; p = 0.001; N = 15). Clutch size for H. mabouia was fixed (two) and mean litter size of the viviparous M. agilis was 3.3 +/- 0.6 (range 3-4; N = 3). Tropidurus torquatus and H. mabouia deposit their eggs under rocks in the study area, with the former burying them but not the latter; in both species, more than one female often oviposit under the same rock.

Animals↗

PubMed2002

Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae) and consequences for adult life history.

Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Aguas Belas Experimental Station-Viamão County), one in a Myrtaceae Forest (Itapuã State Park-Itapuã County) and one in the Atlantic Rain Forest (Maquiné Experimental Station-Maquiné County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this character is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

Animals↗

PubMed2006

Relative fitness of transgenic vs. non-transgenic maize x teosinte hybrids: a field evaluation.

Concern has been often expressed regarding the impact and persistence of transgenes that enter wild populations via gene flow. The impact of a transgene and its persistence are largely determined by the relative fitness of transgenic hybrids and hybrid derivatives compared to non-transgenic plants. Nevertheless, few studies have addressed this question experimentally in the field. Despite the economic importance of maize, and the fact that it naturally hybridizes with the teosinte taxon Zea mays ssp. mexicana, sometimes known as "chalco teosinte," the question has received little experimental attention in this system. Using a glyphosate-tolerant maize cultivar and chalco teosinte as parental lines, we carried out a field experiment testing (1) the relative fitness of maize x teosinte hybrids, compared to their parental taxa, as well as (2) the relative fitness of transgenic hybrids compared to non-transgenic hybrids created from the same parental stock. In order to evaluate the influence of the transgenic construct in different genetic backgrounds, our study included transgenic and non-transgenic pure maize progeny from the cultivar as well. We measured both vegetative and reproductive parameters. Our results demonstrated that hybrids have greater vigor and produced more seeds than the wild parent. However, in the absence of selective pressure from glyphosate herbicide, we did not observe any direct positive or negative impact of the transgene on the fitness or vigor of either the hybrids or pure maize progeny. We discuss our results in terms of the potential for spontaneous transgene flow and introgression from transgenic maize into sympatric teosinte.

Germination↗

PubMed2003

Stress status of gudgeon (Gobio gobio) from rivers in Switzerland with and without input of sewage treatment plant effluent.

To assess the importance of sewage treatment plant effluents on fish health, we studied gudgeon in two rivers in the Swiss midlands (Canton Lucerne). Both rivers receive pollution from diffuse sources, while one also receives the effluent of a sewage treatment plant. Male and female gudgeon during and outside of the spawning season were compared with respect to reproductive parameters and health status across both rivers as well as upstream and downstream of the STP. Several biomarkers were studied, including cytochrome P4501A, 7-ethoxyresorufin-O-deethylase, plasma vitellogenin, ovotestis, lipid, liver histology, condition factor, gonadosomatic index, splenosomatic index, parasites of spleen and liver, population structure, and species diversity. Gudgeons of both rivers exhibited signs of a moderately impaired health status. By a stepwise backward analysis, the cytochrome P4501A content, the splenosomatic index, and the incidence of parasites in the liver were found to provide the best discrimination of the three sampling sites. Evidence of a significant elevation in response to the sewage treatment plant effluent was found neither in vitellogenin concentration nor in the ovotestis rate. While population structure was analyzed upstream and downstream of the sewage treatment plant, only gudgeons of the latter site revealed a disturbed population structure, most probably caused by a former nitrite discharge.

Animals↗

PubMed1995

Intravenous reproductive and developmental toxicity studies of cimadronate (YM175), a novel bisphosphonate, in rats and rabbits.

Cimadronate (YM175) is a novel bisphosphonate with potent inhibitory activity on bone resorption under development for the treatment of tumor-induced hypercalcemia, metastatic bone disease and osteoporosis. We conducted intravenous reproductive toxicity and teratology studies (Segment I, II and III) of this compound in rats and teratology study in rabbits. The test compound was dissolved in physiological saline, which was also given as the vehicle control. Rats were administered at a dosage of 0.06, 0.16 and 0.62 mg/kg/day in the male Segment I study. Dose levels in the other studies in rats including the female Segment I were 0.16, 0.31 and 0.62 mg/kg/day. In the Segment I study, no treatment-related abnormalities were observed in reproductive parameters or fetuses. In the Segment II study, slightly retarded fetal ossification was noted at 0.31 mg/kg/day or more, but the incidence of malformation did not increase. In the Segment III study, death of the dams and abnormal tooth growth of offspring were observed at 0.16 mg/kg/day or more. Further Segment III study showed that the no toxic effect level was 0.003 mg/kg/day. In the rabbit teratology study, dose levels were 0.01, 0.025 or 0.05 mg/kg/day. No toxic effects on pregnant females or their litters were observed at up to 0.05 mg/kg/day.

Abnormalities, Drug-Induced↗

PubMed1998

Reproductive study. II: Prenatal and postnatal development study with candoxatril in Sprague-Dawley rats.

Candoxatril, a prodrug for candoxatrilat, a selective inhibitor of neutral endopeptidase, was administered orally to groups of 24 female rats at doses of 0, 120, 400 or 1200 mg/kg/day from gestation day 6 to lactation day 21 to assess effects on pre- and postnatal development of F1 offspring. All dams were allowed to litter and to raise their F1 offspring until lactation day 21. The F1 offspring were examined for postnatal developmental indices, reflex behaviors and memory. A functional observational battery (FOB) was also conducted. A marked increase in spontaneous activity of the dams was observed in all candoxatril-treated groups. Maternal body weight gain was decreased in the 400 and 1200 mg/kg/day groups during the treatment periods. No significant differences were found for reproductive parameters. The male and female pups in the 1200 mg/kg/day group had significantly lower body weights beginning on postnatal days 21 and 14, respectively, through to the end of the study. There were no drug-related effects on pre- and postnatal developmental indices, FOB, sensory function tests or memory test. The no observed adverse effect levels were 120 and 400 mg/kg/day for the F0 dams and F1 offspring, respectively.

Animals↗

PubMed1995

Effect of ruminally undegradable protein from fish meal on growth and reproduction of peripuberal Brahman bulls.

Thirty-nine Brahman bulls (301.7 +/- 4.1 d; 202.7 +/- 4.7 kg) were allotted to one of two treatments and fed soybean meal (SBM)- or fish meal (FIS)-based supplements and hay to examine the effects of source of protein on growth and reproductive development. The fish meal supplement had 72% ruminally undegradable protein (RUP) and the soybean meal supplement had 47% RUP. Bulls assigned to the FIS treatment had higher (P < .01) total weight gain (81.2 +/- 1.4 vs 71.2 +/- 2.2 kg), higher (P < .01) ADG (.97 +/- .02 vs .85 +/- .03 kg), and better (P < .05) feed:gain ratio (7.6 +/- .1 vs 8.6 +/- .1 feed/BW gain for FIS vs SBM, respectively). Age at first motile spermatozoa was not affected (P > .05) by source of protein (429.9 +/- 9.6 vs 427.2 +/- 9.5 d, for bulls receiving FIS or SBM supplements, respectively). Likewise, age at puberty (473.3 +/- 21.7 d vs 465.9 +/- 12.9 d for bulls receiving FIS and SBM supplements, respectively) was similar for both treatment groups. There were no differences between treatments in scrotal circumference at those stages. At puberty semen quality was similar for bulls receiving FIS or SBM treatments, and no differences existed in LH and testosterone concentrations between treatments. We conclude that fish meal supplement increased growth but did not alter reproductive parameters in Brahman bulls.

Animal Feed↗

PubMed1980

2-Isocyanatoethyl methacrylate--an inhalation dominant lethal study in the male Sprague-Dawley rat.

2-Isocyanatoethyl methacrylate (IEM), a monomer, has been developed for use as a component in coating materials. The dominant lethal test was used to evaluate the mutagenic potential of IEM in rats. In this study, male Sprague-Dawley rats were exposed to 0, 25, 80, or 250 ppb of IEM by inhalation for 6 hr/day for 10 weeks (one spermatogenic cycle). After the exposure period, the males were bred with untreated virgin female rats. At approximately mid-gestation, the females were sacrificed and the number of corpora lutea, implantations, and resorptions were recorded. Statistical analysis of these data indicated that the treated males were comparable to control males in all reproductive parameters evaluated. IEM did not affect male fertility or produce dominant lethal mutations in male rats following ten weeks of inhalation exposure to 25, 80 or 250 ppb IEM.

Acrylates↗

PubMedDate not supplied

Developmental toxicity of dimethyl sulfate by inhalation in the rat.

Dimethyl sulfate (DMS; CAS No. 77-78) is a colorless, oily liquid which is used as a chemical intermediate and as a reactant in producing polyurethane resins. In this study, groups of pregnant Crl:CD BR rats were exposed, nose-only, to either 0.1, 0.7 or 1.5 ppm DMS by inhalation for 6 hr/day from Days 7 through 16 of gestation (day in which copulation plug was detected was designated Day 1G). A control group of pregnant rats was exposed simultaneously to air only. All female rats were euthanized on Day 22G and the fetuses were examined. A suppression of both food consumption and the rate of body weight gain was seen in the 0.7 and 1.5 ppm groups. No unusual clinical signs were seen in rats exposed to DMS. None of the reproductive parameters was altered in any of the groups and no statistically significant fetal effects were detected. DMS is not a developmental toxin in the rat following inhalation exposures up to 1.5 ppm during the period of major organogenesis.

Administration, Inhalation↗

PubMed1991

Recombinant bovine somatotropin with lactating cows fed diets differing in energy density.

Sixty-four Holstein cows (32 primiparous) were assigned randomly at parturition to one of two diets differing in forage:grain ratio and were further assigned to either control or treatment with recombinant bST. A full lactation study was conducted. Total mixed rations consisted of alfalfa silage, high moisture ear corn, soybean meal, and vitamin and mineral supplements. Percentages of forage in the diet (dry basis) for the high and medium energy diets were wk 1 to 12, 38.2 and 58.2; wk 13 to 26, 48.2 and 68.2; and wk 27 to 44, 68.2 and 88.2. Injection of a saline placebo or 20.6 mg/d per cow of bST started at wk 13 and stopped at wk 43 of lactation. Administration of bST increased 305-d milk yield by 19.9 and 18.3% for multiparous cows fed high and medium grain diets and by 13.0 and 5.9% for primiparous cows fed the same diets. Body weight gain during lactation tended to be lower for cows treated with bST, and body condition scores were significantly lower for those treated with bST and fed the medium energy diets. Daily injection of bST did not change concentrations of glucose or urea in blood or beta-hydroxybutyrate in plasma. Multiparous cows had a transitory increase in plasma FFA concentration immediately after bST treatment started. Milk composition, health, and reproductive parameters observed were not adversely affected by bST administration. Cows fed low energy diets during bST administration in the first lactation did not produce as much milk as controls when compared during the first 10 wk of their second lactation.

Animal Feed↗