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PubMed2002

Relationships between body weight at first mating and subsequent body development, feed intake, and reproductive performance of rabbit does.

A retrospective study was performed to evaluate the relationships between BW at first insemination and subsequent body development, feed intake, reproductive performance, and culling rate of rabbit does. Young rabbit does are vulnerable to body energy deficit in first lactation, resulting in decreased reproductive performance and high replacement rate. Heavy does at first insemination might be able to benefit from the extra amount of BW to cope with the energy deficit during first lactation. Data of three experiments were used in which does were given ad libitum access to feed during rearing and inseminated at 14.5 wk of age. The first two parities of each doe were recorded. Does were categorized in three groups based on their BW at 14.5 wk of age (first insemination): heavy (BW > or = 4,000 g), medium (BW 3,500 to 4,000 g), and small (BW < 3,500 g). Among does that kindled, differences in BW at first insemination were related to differences in voluntary feed intake and body growth rate during rearing. Heavy does consumed more feed per day (+ 45 g/d, P < 0.001) and had a higher BW gain (+ 12 g/d, P < 0.001) than small does from weaning (4.5 wk) to 14.5 wk of age. Body weight at first insemination did not affect BW, feed intake, and culling rate during the first two parities. Heavy does were heavier at first insemination and remained so throughout the reproductive period, but they followed a similar BW curve as medium and small does. A higher BW at first insemination (14.5 wk of age) improved litter size in the first parity (8.9, 7.7, and 6.4 for heavy, medium, and small does, respectively, P < 0.05). Extra BW at start of reproduction improves litter size in the first parity but does not contribute to an improved feed intake or increased BW development during reproduction.

Animal Husbandry↗

PubMed2004

Long-term exposure of several marine benthic animals to static magnetic fields.

Electrical currents in underwater sea cables could induce magnetic fields. The sea cables lie on or within the sea bottom and this is the living area for many invertebrate and vertebrate species. North Sea prawn Crangon crangon (Crustacea, Decapoda), round crab Rhithropanopeus harrisii (Crustacea, Brachyura), glacial relict isopod Saduria entomon (Crustacea, Isopoda), blue mussel Mytilus edulis (Bivalvia), and young flounder Plathichthys flesus (Pisces) were exposed to a static magnetic field (MF) of 3.7 mT for several weeks. The results showed no differences in survival between experimental and control animals. Mussels M. edulis were kept under static magnetic field conditions for 3 months during their reproductive period in spring. The determination of gonad index and condition index revealed no significant differences to the control group.

Animals↗

PubMed1989

Molecular cloning of two cDNAs for related secretory proteins in lizard epididymis: gene expression during androgen-induced cell growth and secretion.

Lizard epididymis is an androgen-dependent tissue which produces notably ten related secretory proteins (L-proteins, Mr 19,000) during the reproductive period. These proteins were synthesized in vitro as preproteins (Mr 25,000, 24,000, 23,500). A cDNA library in the plasmid pBr322 was constructed and two cDNA clones were isolated by differential hybridization according to the differential expression of the mRNAs in stages 1 and 6 of the annual reproductive cycle. Translations of mRNAs hybrid-selected by two clones (LV123, LV132) yielded proteins which were immunoprecipitated by the L-antiserum. These preproteins were processed in vitro into six peptides; four were encoded by mRNAs selected with the LV123 clone, the others by the LV132 clone. Only three bands were detected using Northern blot analysis suggesting that the L-family could be derived from various mRNAs and from post-translational maturations. Southern analysis of genomic DNA suggests that the L-mRNAs were encoded by at least two distinct genes which could exist in numerous copies. The L-gene expression was studied under various physiological conditions and was found to be androgen-dependent. Furthermore, the results suggest the presence of a translational regulation in the newly differentiated epithelial cells.

Androgens↗

PubMed2005

Reproduction and ulcerative colitis: a review.

Ulcerative colitis is a chronic inflammatory bowel disease. The onset peaks at age 15-30 years and coincides with the reproductive period. We screened and summarized the relevant English-language publications (Entrez-PubMed) on ulcerative colitis, fertility and pregnancy. The presence of ulcerative colitis per se does not seem to significantly alterfertility in young women. However, associated conditions, such as active disease, surgical interventions and medication, may interfere with reproduction. It is difficult to draw conclusions regarding the effect of ulcerative colitis on pregnancy outcome in terms of pregnancy loss, intrauterine growth restriction, low birth weight, preterm labor, stillbirth and perinatal mortality. Nevertheless, it appears that major complications do not occur in ulcerative colitis patients more frequently than in healthy women. The rate of exacerbation is probably the same for pregnant and nonpregnant women. Disease control during pregnancy is of the utmost importance. Fortunately, most drugs can by used safely during pregnancy.

Adolescent↗

PubMed2006

[The influence of ecdysone-containing phytopreparations on life span of Drosophila melanogaster strains depending on the genotype].

The longevity of Drosophila strains has been investigated after treatment by a hormone 20-hydroxyecdysone (80% solution) and a phytoecdysteroid-containing metaverone preparation (contains 5-7% of 20-hydroxyecdysone) in preimaginal stages of development. It is shown, that life expectancy of ecdysone-deficient woc strain exceeds life expectancy of wild type Canton-S strain by 46%, whereas ecdysone or metaverone treatment removes these distinctions. At the same time, treatment by ecdysteroid-containing preparations of Canton-S has not induced any essential alteration of life span. Thus, the new ageing gene woc has been discovered, the woc mutation essentially increases the life span of Drosophila, and its effect is mediated by a hormone 20-hydroxyecdysone and has the threshold corresponding natural physiological concentration of this hormone in an insect organism. The data have confirmed the conception of "antagonistic pleiotropy" according to which only mutations having advantages during the prereproductive and reproductive period are fixed in evolution, and their negative effect is delayed up to a postreproductive stage of life cycle. As a result we can see accumulation with age of structural and functional damages which increase probability of death. Indeed, genes of ecdysone synthesis play fundamentally important role in early development and sexual reproduction of insects, however essentially reduce their life span.

Aging↗

PubMed1992

Circadian rhythm of photosensitivity and the adaptation of reproductive function to the environment in two populations of Arvicanthis niloticus from Mali and Burkina Faso.

Previous studies have shown that there is a circadian rhythm of photosensitivity in different rodent species of the Sahel (Burkina Faso) and that, despite the low amplitude of seasonal variations in daylength, the photoperiod may control reproductive function. The present investigation of Arvicanthis niloticus provides additional support for this hypothesis. Populations of Arvicanthis niloticus from two regions at the same latitude 1000 km apart but with different climates were studied. Oursi, Burkina Faso, has an arid climate (annual rainfall 315 mm) and Kamalé, Mali has a wetter climate (annual rainfall 1114 mm). The circadian rhythm of photosensitivity had the same features in both populations, involving inhibition of testicular activity, but the photosensitive phase began 11 h 30 min after dawn in the population from Burkina Faso and 45 min later in that from Mali. Comparison of these results with the annual variation of daylength showed that the photoperiod inhibits the reproductive activity of A. niloticus from April to December in Burkina Faso and only from mid-May to mid-August in Mali. The population of Arvicanthis niloticus living in an environment with a large and seasonally stable food supply (Mali) thus has a longer reproductive period. This corroborates results from field studies on annual variations of population density.

Adaptation, Physiological↗

PubMed1979

Similarities in the regulatory patterns of pregnant and cycling rats.

The patterns of food intake, water intake and body weight of the female rat during the estrous cycle and pregnancy were determined. During the 4-day estrous cycle, intake and body weight were reduced on the day of ovulation. In contrast, animals with 5-day estrous cycles reduced intake and body weight for 2 days, the day prior to ovulation as well as on the day of ovulation. Intake of pregnant rats around the time of birth was compared to that of cycling females and similarities were observed. The peripartum pattern of food intake was systematically related to the length of the gestation period. Rats that littered 22 days after mating showed depressed food intake only on the day of birth. Those with 23-day gestation periods decreased food intake both on the day of birth and on the following day. The similarities in the intake patterns during 4- and 5-day estrous cycle to that of the peripartum segment of 22- and 23-day pregnancies suggest that there may be common neuroendocrine factors controlling these behaviors during the two reproductive periods.

Animals↗

PubMed2003

Steroid production in toads.

In Bufo arenarum, androgen biosynthesis occurs through a complete 5-ene pathway, including 5-androstane-3beta,17beta-diol as the immediate precursor of testosterone. Besides, steroidogenesis changes during the breeding period, turning from androgens to C(21)-steroids such as 5alpha-pregnan-3alpha,20alpha-diol, 3alpha-hydroxy-5alpha-pregnan-20-one and 5alpha-pregnan-3,20-dione. In B. arenarum, steroid hormones are not involved in hCG-induced spermiation, suggesting that the steroidogenic shift to C(21)-steroids during the breeding be not related to spermiation. The activity of 17-hydroxylase-C(17-20) lyase (CypP450(c17)) decreases during the reproductive season, suggesting that this enzyme would represent a key enzyme in the regulation of seasonal changes. However, the increase in the affinity for pregnenolone of 3beta-hydroxysteroid dehydrogenase (3alphaHSD)/isomerase could also be involved. Moreover, the reduction in CypP450(c17) leading to a reduction in C(19)-steroids, among them dehydroepiandrosterone (DHE), would contribute to the conversion of pregnenolone into progesterone, avoiding the non-competitive inhibition exerted by DHE on this transformation. Additionally, CypP450(c17) possesses a higher affinity for pregnenolone than for progesterone, explaining the predominance of the 5-ene pathway for testosterone biosynthesis. Animals in reproductive condition showed a significant reduction in circulating androgens, enhancing the physiological relevance of all the in vitro results. The in vitro effects of mGnRH and hrFSH on testicular steroidogenesis revealed that both hormones inhibited CypP450(c17) activity. In summary, these results demonstrate that, in B. arenarum, the change in testicular steroidogenesis during the reproductive period could be partially due to an FSH and GnRH-induced decrease in CypP450(c17) activity.

Androgens↗

PubMed2003

Timing of autumn bird migration under climate change: advances in long-distance migrants, delays in short-distance migrants.

As a response to increasing spring temperature in temperate regions in recent years, populations of many plant and animal species, including migratory birds, have advanced the seasonal start of their reproduction or growth. However, the effects of climate changes on subsequent events of the annual cycle remain poorly understood. We investigated long-term changes in the timing of autumn migration in birds, a key event in the annual cycle limiting the reproductive period. Using data spanning a 42-year period, we analysed long-term changes in the passage of 65 species of migratory birds through Western Europe. The autumn passage of migrants wintering south of the Sahara has advanced in recent years, presumably as a result of selection pressure to cross the Sahel before its seasonal dry period. In contrast, migrants wintering north of the Sahara have delayed autumn passage. In addition, species with a variable rather than a fixed number of broods per year have delayed passage, possibly because they are free to attempt more broods. Recent climate changes seem to have a simple unidirectional effect on the seasonal onset of reproduction, but complex and opposing effects on the timing of subsequent events in the annual cycle, depending on the ecology and life history of a species. This complicates predictions of overall effects of global warming on avian communities.

Animals↗

PubMed1995

Multihormonal control of vitellogenin mRNA expression in the liver of frog, Rana esculenta.

In Rana esculenta in an in vitro system, hepatic vitellogenin synthesis can be induced by growth hormone in both sexes. In this study: (1) the ability of this hormone to induce transcription of the VTG gene was determined, and (2) this ability was compared with that of estradiol-17 beta. The results indicate that growth hormone stimulates VTG mRNA transcription both in vivo and in vitro, in both sexes. The levels of mRNA are related to protein levels in the medium. In addition, seasonal variation occurs in the VTG gene transcription under growth hormone and estradiol-17 beta; indeed the more active inducer was growth hormone during the reproductive period and estradiol-17 beta during the preproductive phase.

Animals↗

PubMed1998

D-aspartic acid is implicated in the control of testosterone production by the vertebrate gonad. Studies on the female green frog, Rana esculenta.

In the present study we report the occurrence of D-aspartic acid (D-Asp) in the ovary of the green frog Rana esculenta and its putative involvement in testosterone production by the gonad. In the ovary, D-Asp concentrations undergo significant variations during the main phases of the sexual cycle. In spawning females (March), its concentration was low (2.5 +/- 1.1 nmol/g ovary) and during the post-reproductive period (June) it increased and reached its peak level (58.0 +/- 10.1 nmol/g) in October. In that month, vitellogenesis occurs in a new set of ovarian follicles and continues until the next spring. The concentrations of D-Asp in the ovary and of testosterone in the ovary and in the plasma were inversely correlated during the reproductive cycle: when endogenous D-Asp was low (March), testosterone was high (36.9 +/- 4.8 ng/g ovary; 23.1 +/- 2.76 ng/ml plasma) and, in contrast, when the D-Asp concentration was high (October), the testosterone concentration was low (0.86 +/- 0.21 ng/g ovary and 5.0 +/- 1.3 ng/ml plasma). In vivo experiments, consisting of injection of D-Asp (2.0 mumol/g body weight) into the dorsal lymphatic sac of adult female frogs, demonstrated that this amino acid accumulates significantly in the ovary. After 3 h, moreover, it caused a decrease in testosterone level in the plasma of about 80%. This inhibition was reversible: within 18 h after the amino acid injection, as the D-Asp concentration in the ovary decreased, the testosterone titre was restored in both ovary and plasma. In vitro experiments, conducted in isolated ovarian follicles, confirmed this phenomenon and identified these gonadal components as the putative D-Asp targets. Other amino acids (L-Asp, D-Glu, L-Glu, D-Ala and L-Ala) used instead of D-Asp were ineffective. These findings indicate that D-Asp is involved in the control of androgen secretion by the ovary in this amphibian species, revealing a more complex system for control of this androgen synthesis than was previously believed to exist.

Amino Acids↗

PubMed1975

[The response of the hypophysis to exogenous Gn-RH during the annual reproductive cycle of the carp Cyprinus carpio L].

The response of the hypophysis to injection of homologous hypothalamic extract and of LH-RH was studied during the reproductive cycle of the Carp Cyprinus carpio L. It is maximal during the summer months, during the reproductive period. It is nil or weak during winter, the period of sexual inactivity. It appears in April-May when gametogenesis is initiated and the water temperature increase.

Animals↗

PubMed2004

Beta-naphthoflavone alters normal plasma levels of vitellogenin, 17 beta-estradiol and luteinizing hormone in sea bass broodstock.

A variety of environmental pollutants exhibit antiestrogenic properties, i.e. these compounds antagonize estrogen-dependent processes in their target tissues. This is the case with beta-naphthoflavone (beta NF), a compound that is known for its ability to bind to the arylhydrocarbon receptor (AhR) and thereby to induce cytochrome P4501A (CYP1A) expression. In previous studies, we have shown that beta NF antagonizes the 17 beta-estradiol (E2)-mediated production of vitellogenin (VTG) in cultured rainbow trout hepatocytes in vitro. This antiestrogenic effect appeared to be related to the beta NF activation of the AhR pathway. The questions addressed in the present study are: (a) if beta NF is able to evoke an antiestrogenic effect in fish in vivo; this was estimated from circulating VTG levels, and (b) if the antiestrogenic action is expressed not only at the cellular (suppressed VTG synthesis) but also at the systemic level; this was addressed by measuring the circulating level of two hormones directly implicated in the regulation of reproductive processes: E2 and luteinizing hormone (LH). As experimental model, we used broodstock sea bass (Dicentrarchus labrax). The fish were fed with a beta NF-enriched diet from December, at the beginning of the reproductive period of sea bass, until the termination of this period in April. Induction of hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity and CYP1A mRNA levels in beta NF-fed fish indicates that the test compound was accumulated and effective. Compared to the control fish, beta NF treatment of sea bass was associated with a significant reduction of plasma VTG levels, and it disturbed the reproduction-related fluctuations of plasma E2 and LH levels. These findings point to an antiestrogenic effect of beta NF on VTG synthesis and to an interference with the hypothalamus-pituitary-gonad axis in reproducing sea bass.

Animals↗

PubMed1992

Reproductive factors and risk of thyroid cancer. A prospective study of 63,090 women from Norway.

This prospective study of 63,090 Norwegian women with 124 cases of thyroid cancer diagnosed during 1961-1989 revealed no strong associations with reproductive factors. Late last birth was related to increased risk, whereas no association was noted with parity. A long reproductive period was related to increased risk of papillary carcinomas, whereas a decreased risk of follicular carcinomas and other adenocarcinomas was observed in women with early menarche and late menopause. The risk of thyroid cancer was significantly increased among women in the occupational category 'fishing, ships officers and crew'. Our results are consistent with a modest effect of certain reproductive factors upon thyroid cancer development.

Adult↗

PubMed1999

Galanin in the lizard oviduct: its distribution and relationships with estrogen, VIP and oviposition.

The distribution of neurons containing galanin immunoreactivity (Gal/IR) has been detected in the oviduct of the lizard Podarcis s. sicula during the main phases of its sexual cycle and after 17beta-estradiol treatment. Indirect immunofluorescence technique was applied both to cryostatic sections and whole mount preparations, and Western blot analysis, with an antibody directed against mammalian galanin (Gal), was performed with lizard oviduct extracts. Colocalization of Gal with vasoactive intestinal polypeptide (VIP) was also studied as well as Gal effects on egg deposition. In the quiescent oviduct of non-reproductive females, scanty Gal/IR fibres were found in the uterine-vaginal segment. During the reproductive period a gradual increase of positive nerve fibres and cell bodies were found distally in the lizard oviduct and the vagina revealed a reactive nerve population denser than elsewhere. Gal-IR nerve structures were present either in the musculature or mucosa and in the intermuscular layer they were organized in a nerve network. In the oviduct of non-reproductive females, 17beta-estradiol administration induced a significant increase of neurons containing Gal/IR. This hormone could be involved in the egg laying by means of galanin action and this hypothesis is supported by the induction of premature oviposition in pre-ovulatory females after Gal administration. Western blot analysis validates this peptide as true Gal, recognising one protein band with a molecular weight (3.2 kDa), similar to that of porcine Gal. Double labelling studies showed the co-presence of Gal and VIP in some neurons.

Animals↗

PubMed1992

Reproductive toxicity of triethylene glycol and its diacetate and dimethyl ether derivatives in a continuous breeding protocol in Swiss CD-1 mice.

Triethylene glycol and two of its derivatives were evaluated for reproductive toxicity in a continuous breeding protocol with Swiss CD-1 mice. Triethylene glycol (TEG: 0, 0.3, 1.5, and 3%), triethylene glycol diacetate (TGD: 0, 0.75, 1.5, and 3%), and triethylene glycol dimethyl ether (TGDME: 0, 0.25, 0.5, and 1%) were administered in drinking water to breeding pairs (20 pairs per treatment group, 40 control pairs) during a 98-day cohabitation period. Reproductive function was assessed by the number of litters per pair, live pups per litter, proportion of pups born alive, and pup weight. There were no apparent effects on reproductive function in the animals receiving TEG or TGD at doses up to 3% in the drinking water (representing 6.78 or 5.45 g/kg, respectively). However, some developmental toxicity was demonstrated for both TEG and TGD. Continuous exposure of dams to 1.5 or 3% TEG significantly reduced live pup weight at birth compared to control and 0.3% TEG, while exposure to 3% TGD during lactation significantly (but reversibly) reduced pup body weights on Postnatal Days 14 and 21. In contrast, TGDME was toxic to the reproductive system as evidenced by decreases at the highest dose (1% TGDME; 1.47 g/kg) in the proportion of pairs that produced at least one litter, live pups per litter, and proportion of pups born alive, with dose-related trends seen in the latter two parameters. A crossover mating trial showed that TGDME was more toxic to the female than the male reproductive system. These data indicate that TGDME (1.47 g/kg) is a reproductive toxicant in Swiss mice while reproductive toxicity was not demonstrated in mice receiving TEG or TGD (at doses up to 6.78 or 5.45 g/kg, respectively).

Animals↗

PubMed2004

Gynecologic and obstetric findings related to nutritional status and adherence to a gluten-free diet in Brazilian patients with celiac disease.

This study shows a broad analysis of gynaecological and obstetrical disturbances in patients with celiac disease in relation to their nutritional status and adherence to a gluten-free diet. Seventy-six adult celiac patients were analyzed according to nutritional status and 18 children/adolescents to gluten-free diet adherence. As controls, 84 adults and 22 adolescents with irritable bowel syndrome were used The significant findings were observed as follow: adult celiac patients, irrespective of the nutritional status, were younger than controls, presented delayed menarche, secondary amenorrhea, a higher percentage of spontaneous abortions, anemia and hypoalbuminemia. No differences were observed regarding the number of pregnancies, age at menopause and duration of the reproductive period. After treatment, patients presented with normal pregnancies and one patient presented spontaneous abortion. The adolescents who were not adherent to gluten-free diet presented delayed menarche and secondary amenorrhea. In conclusion, gluten per se could explain the disturbances and malnutrition would worsen the disease in a consequent vicious cycle. Therefore, celiac disease should be included in the screening of reproductive disorders.

Abortion, Spontaneous↗

PubMed2004

Importance of log size on host selection and reproductive success of Ips pini (Coleoptera: Scolytidae) in ponderosa pine slash of northern Arizona and western Montana.

Pine engraver, Ips pini (Say), often use thinning slash, and their populations are known to be influenced by the condition of this material. In our study, we evaluated the importance of three log diameters (5, 10, and 20 cm) and three lengths (60,120, and 240 cm) on various parameters of bark beetle host attack, development, and emergence. Evaluation of slash colonization in northern Arizona (near Flagstaff) and western Montana (near Missoula) over several years, during both spring and summer reproductive periods, indicated that the size of material selected by pine engraver differed by state, year, and season. However, within individual trials and over all trials, a trend in preference for larger diameter logs was apparent, whereas log length was of little effect. When evaluating only attacked logs, results indicated that the apparent preference for larger logs was not followed by significantly greater reproductive performance in the larger log sizes. Log origin was tested as a potential factor for the difference in attack densities between Arizona and Montana trials. Although male beetles in Montana and female beetles in Arizona seemed to distinguish between local-source and foreign-source logs during the attack phase, the gallery development and reproductive success of egg, larval, and new adult stages were not significantly different. Ultimately, differences among the trials both in host size selection and in reproductive success within attacked logs were closely tied to the overall population density of adult beetles. The implications of these findings for resource managers are discussed.

Animals↗