Journal of reproduction and fertility. Supplement最新文献

{"title":"Endocrinology of the lactating and weaned sow.","authors":"M. Varley, G. Foxcroft","doi":"10.1530/biosciprocs.13.004","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.004","url":null,"abstract":"","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"128 1","pages":"47-61"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79566524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Basic physiology of follicular maturation in the pig.","authors":"G. Foxcroft, M. Hunter","doi":"10.1530/biosciprocs.12.001","DOIUrl":"https://doi.org/10.1530/biosciprocs.12.001","url":null,"abstract":"The pig is an excellent animal in which to study the control of folliculogenesis in a polytocous species, and particularly to examine the inter-relationships between follicles from the same animal. Follicle recruitment occurs from the proliferating pool, and various studies suggest that this recruitment occurs between Days 14 and 16 of the oestrous cycle. The growth of follicles selected for ovulation is associated with rapid atresia of smaller follicles and a block to their replacement in the proliferating pool. However, there is a considerable range in the morphological and biochemical development of the dominant follicles in the early follicular phase, suggesting that follicles are recruited at markedly different stages of development, or that recruitment continues into the follicular phase. A significant and predictable relationship has been established between follicular diameter and follicular fluid volume, and a comparison of these two characteristics demonstrates a gradual increase in follicular tissue volume as a proportion of total volume. Growth of follicles from 2 to 4 mm is associated with a proportional increase in granulosa cell numbers, but above 4 mm the relationship is very variable even in selected follicles that are steroidogenically active. Therefore, the number of granulosa cells cannot be used as an indicator of atresia in pig follicles. LH receptors are present in thecal tissue throughout development, reaching maximal levels on Day 20 of the oestrous cycle and declining on Day 21. Granulosa cells possess receptors for LH only in the later stages of maturation, and again these are maximal on Day 20. The pattern of steroidogenesis in pig follicles is consistent with the two-cell theory of steroidogenesis in that androgen produced by the theca is aromatized to oestrogen by the granulosa cells, However, in contrast to that of many other species, the theca of the pig also produces oestradiol in quantities comparable to those secreted by the granulosa. As with morphological development, the selected population of preovulatory follicles shows a considerable range of biochemical development and follicles of identical size may show great dissimilarity in follicular fluid steroid concentrations and LH binding. Androgen availability rather than aromatase activity appears to be the limiting factor for steroidogenesis. There are also several nonsteroidal factors which have been isolated from porcine tissue and play some role in follicular maturation. Although exogenous gonadotrophins are effective in promoting follicular development, other factors of extra- or intra-ovarian origin may limit follicular responsiveness to gonadotrophins.(ABSTRACT TRUNCATED AT 400 WORDS)","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"8 1","pages":"1-19"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75313070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uterine and ovarian countercurrent pathways in the control of ovarian function in the pig.","authors":"T. Krzymowski, J. Kotwica, S. Stefańczyk-Krzymowska","doi":"10.1530/biosciprocs.13.0013","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0013","url":null,"abstract":"","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"6 1","pages":"179-91"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75801375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immune-endocrine interactions affecting luteal function in pigs.","authors":"Wolfgang Wuttke, L. Pitzel, I. Knoke, K. Theiling, H. Jarry","doi":"10.1530/biosciprocs.15.002","DOIUrl":"https://doi.org/10.1530/biosciprocs.15.002","url":null,"abstract":"The formation, normal function and destruction of corpora lutea are essential features of normal reproduction. Although the formation of corpora lutea from follicles is largely dependent on pituitary gonadotrophins, the process of luteolysis is locally regulated and poorly understood. The corpus luteum consists of several steroidogenic and nonsteroidogenic cell types that interact with each other in a paracrine manner. Under cell culture conditions, large luteal cells that stem from follicular granulosa cells can be identified easily under the microscope and collected individually for single cell RT-PCR. As each of the 120 large luteal cells express the gene encoding 3 beta-hydroxysteroid dehydrogenase, it appears that all large luteal cells are steroidogenic. Large luteal cells also express the oestrogen receptor gene and as they are known to produce oestradiol, it can be concluded that the steroid acts in an auto- or intracrine manner in large luteal cells. Since we showed previously that oestradiol stimulates progesterone release under in vitro and in vivo conditions, it can be concluded that the steroid is an important intraluteally acting luteotrophic signal. At the time of luteal regression, macrophages invade the corpora lutea and their cytokine products, particularly tumour necrosis factor alpha (TNF alpha), appear to be involved in reduced steroid secretion. Indeed, TNF alpha inhibits production of progesterone and oestradiol from cultivated luteal cells. In sows, oestradiol is a strong luteotrophic factor and the production of oestradiol and of its receptor is downregulated by TNF alpha. Thereby, TNF alpha not only exerts direct luteolytic effects but also prevents the luteotrophic effects of oestradiol. Hence, it has an anti-luteotrophic action. In most species, functional luteolysis is accompanied by morphological regression of the corpus luteum. This structural luteolysis also appears to involve TNF alpha, as we have shown in pigs that expression of TNF alpha gene is high during luteolysis. Furthermore, TNF alpha stimulates programmed cell death (apoptosis) in luteal cells kept under culture conditions.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"4 1","pages":"19-29"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90771527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Embryonic steroids and the establishment of pregnancy in pigs.","authors":"R. Geisert, M. T. Zavy, R. Moffatt, R. Blair, T. Yellin","doi":"10.1530/biosciprocs.13.0021","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0021","url":null,"abstract":"In the pig, establishment of pregnancy begins about 11-12 days after the start of oestrus. The ability of pig conceptuses to synthesize and release oestrogens during this period, as well as the ability of exogenous oestrogens to induce pseudo-pregnancy when administered from Day 11-15 of the oestrous cycle, provide evidence for an involvement of oestrogen in the maternal recognition of pregnancy in the sow. Oestrogen derived from the conceptus or from administration to cyclic gilts stimulates uterine secretion of calcium and specific polypeptides on Day 11-12. The specific roles for the uterine secretory response to oestrogen in the maintenance of pregnancy are unknown. However, it has been proposed that oestrogen prevents luteolysis in the sow through reorientation of endometrial prostaglandin release, i.e. into the uterine lumen rather than into the uterine vasculature. Oestrogen may interact with prolactin and/or conceptus secretory proteins to shift the direction of prostaglandin movement. Although conceptus oestrogen synthesis triggers a number of uterine secretory events on Day 11, a second sustained phase of oestrogen stimulation from Day 14 to 18 appears to be necessary for luteal maintenance beyond Day 25. Pig conceptuses synthesize and release large amounts of oestrogens between Days 14 and 18 of pregnancy. Conceptus oestrogens are clearly involved with the establishment of pregnancy. However, the conceptus also secretes a number of biologically active substances such as catechol oestrogens, prostaglandins and polypeptides which could interact with oestrogen to prevent luteolysis. The roles of these factors in control of vascular permeability, blood flow, placental attachment and immunological protection certainly indicate that, in addition to oestrogens, other factors are involved in the establishment of pregnancy in pigs.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"736 1","pages":"293-305"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78769004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physiology of the Meishan boar.","authors":"D. Lunstra, J. Ford, J. Klindt, T. Wise","doi":"10.1530/biosciprocs.15.0013","DOIUrl":"https://doi.org/10.1530/biosciprocs.15.0013","url":null,"abstract":"Onset of puberty (sperm production) occurs at a much younger age (56-84 days) in Meishans than in conventional boars (120-180 days). Throughout postnatal development, Meishans exhibit markedly higher (two- to ten-fold) concentrations of serum FSH, LH and androgens compared with conventional boars, and these high hormone concentrations are maintained at maturity. Increased gonadotrophin concentrations occur only in Meishan males, since concentrations in female Meishans and conventional females do not differ. In the Meishan boar, FSH increases steadily during establishment of sperm production and LH increases markedly after tubule diameter stabilizes, while FSH and LH concentrations are low and change little during this period of rapid testicular growth in conventional boars. The proportion of the testis occupied by Leydig cells is two-fold greater and average Leydig cell size is two- to four-fold larger in Meishans than in conventional boars during the onset of spermatogenesis and into maturity. Testis size in Meishans is only half that of conventional boars at maturity, and the number of Sertoli cells is markedly reduced in Meishans. However, Meishan testes exhibit reduced degeneration of germ cells and spermatids during spermatogenesis, and spermatogenic efficiency per Sertoli cell in Meishans is double that in conventional boars. At maturity, Meishan pituitaries have greater mass, larger gonadotrophs, higher content of FSH, and greater expression of genes for FSH and LH subunits than found in conventional boars. The high concentrations of serum gonadotrophins in the mature Meishan exhibit a typical postcastration rise, respond to GnRH stimulation and are suppressed by gonadal steroids, indicating that the hypothalamo-pituitary-gonadal axis functions normally but with much higher set points in Meishan boars. These unusual endocrine and physiological attributes in boars of the highly prolific Meishan breed offer a unique model for further investigation of factors influencing early onset of puberty and efficiency of male reproductive function.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"92 1","pages":"181-93"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88161946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the ovary and conceptus on uterine blood flow in the pig.","authors":"S. Ford, S. Stice","doi":"10.1530/biosciprocs.12.006","DOIUrl":"https://doi.org/10.1530/biosciprocs.12.006","url":null,"abstract":"Changes in uterine blood flow throughout pregnancy appear to be due to steroid-induced alterations in uterine arterial tone and contractility. Arterial contractility is a transient reduction in luminal diameter in response to nerve stimulation or to an alpha-1 adrenergic agonist, leading to short-term reduction in uterine blood flow. Tone is the pressure exerted by an arterial segment against an intraluminal flow (distensibility) and is considered to set the baseline rate of flow. These phenomena appear to be regulated individually, with tone changes predominating during pregnancy. In pregnancy, tone is markedly depressed as oestrogen concentrations rise, and the vessel is distended and flaccid. Arterial tone is a function of the amount of calcium available to the contractile proteins of the arterial smooth muscle, which is derived from extracellular sources. Calcium availability is regulated by the opening and closing of calcium channels in the surface membrane in response to changes in the membrane potential. The loss of uterine arterial tone associated with oestrogen results from a markedly depressed uptake of calcium by the vessels. A significant negative correlation (P less than 0.001; r = - 0.93) is observed between uterine arterial uptake of calcium and the concentrations of oestrogens in systemic blood of pigs throughout gestation. Several lines of evidence suggest that the blockade of potential-sensitive calcium channels associated with uterine hyperaemia is produced by catechol oestrogens, short-lived metabolites of oestrogens that are found in the circulation when oestrogen levels are high. Synthesis of catechol oestrogens from the parent oestrogens has been shown to occur in the placenta, endometrium and uterine arteries of pigs.(ABSTRACT TRUNCATED AT 250 WORDS)","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"9 1","pages":"83-90"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84250681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Embryonic and uterine development during early pregnancy in pigs.","authors":"H. Stroband, T. van der Lende","doi":"10.1530/biosciprocs.13.0019","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0019","url":null,"abstract":"Comparison of the timing of pig preimplantation development, alterations in the ultrastructure of embryonic germ layers, and cytological changes of the uterine epithelial cells leads to the supposition that a close relationship exists between embryonic and uterine development during early pregnancy. The results of in-vitro studies of embryonic development and of experiments concerning asynchrony between embryos and uterine environment confirm this supposition, especially as far as the post-hatching period is concerned. It is suggested that successive steps in embryonic germ layer differentiation may induce specific developmental events and secretory activity of the embryos. A mutual influence of maternal and embryonic tissues appears to exist, but we can only speculate about the causes of many of the described phenomena.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"71 1","pages":"261-77"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86124086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic influences on hypothalamic-pituitary-ovarian function in the pig.","authors":"P. Booth","doi":"10.1530/biosciprocs.13.007","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.007","url":null,"abstract":"A relationship between nutrition and reproduction hag been known to exist for a considerable time, aIthough the physiological mechanisms mediating these effects are only beginning to be elucidated. Body weight, fatness or body composition have all been suggested to play an important role in the long-term control of reproductive function. However, there is now evidence to indicate that nutritional modulation of the reproductive axis can occur in the absence of any change in body weight or composition and that factors regulating the metabolic status of an animal may provide a link between nutrition and reproduction. These physiological signals appear to involve metabolit hormones and substrates. This review will briefly describe the influence of nutrition on plasma substrate concentrations, metabolic hormones and neurotransmitter activity and the mechanisms by which these physiological signals affect the activity of the hypothalamo—hypophysial—ovarian axis. Subsequently, this paper will review experiments in pigs and other species which have directly investigated the mechanisms by which manipulation of nutrition or metabolic status influence reproductive function during the prepubertal period, in sexually mature animals and also during the post-partum period.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"49 1","pages":"89-100"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77945004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The synthesis and actions of steroids and prostaglandins during follicular maturation in the pig.","authors":"L. Ainsworth, B. Tsang, B. Downey, G. J. Marcus","doi":"10.1530/biosciprocs.13.0010","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0010","url":null,"abstract":"Our understanding of the synthesis and production of follicular steroids and prostaglandins (PG) in the pig is based largely on in-vitro studies with granulosa and theca interna tissues obtained from Graafian follicles at various stages of maturation. As the follicle enlarges before the LH surge, granulosa cells exhibit a decrease in FSH receptors and are less responsive to FSH in terms of cAMP production. Concurrently, there is an increase in granulosa and thecal cell LH receptors associated with an increase in responsiveness to LH and an increase in steroid production. Both granulosa and thecal cells produce oestrogen and progesterone, the rates of production being dependent on the stage of maturation of the follicle and substrate availability. Thecal cells are the principal source of androgens and control oestrogen synthesis by providing aromatizable substrate. After exposure to LH/hCG in vivo, both cell types lose the ability to produce oestrogen in vitro. These studies support the two-cell, two-gonadotrophin hypothesis of ovarian steroidogenesis. In vitro, granulosa and thecal cells exhibit an increased ability to produce PGE-2 and PGF-2 alpha after exposure to LH/hCG in vivo. Follicular PG production appears to be regulated by arachidonic acid availability and PG synthetase activity. In vivo, the follicular fluid concentrations of PGE-2 and PGF-2 alpha increase markedly at the time of ovulation. The increases in PG levels and ovulation can be blocked by indomethacin, an inhibitor of PG synthesis. These studies provide convincing evidence for an intrafollicular source of PGs and are consistent with the hypothesis that LH induces an increase in PG production that is essential for rupture of the follicle. Steroids act on the follicle through autocrine and paracrine mechanisms to modulate follicular growth and differentiation and to regulate steroidogenesis. PG actions on the follicle appear to be exerted via effects on contractile elements of the theca externa, blood vessels and on collagenolytic and other proteolytic enzymes.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"16 1","pages":"137-50"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86223004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}