牲畜生殖内分泌学课件.ppt

1、Clinical Reproductive EndocrinologyJacky ChanClinical Reproductive Endocrinology Reproductive hormones Assay methods Physiology of reproductive hormones in the female Clinical aspects of reproductive endocrinology General commentsReproductive hormones Definition of hormones Chemical classes of repro

2、ductive hormones Hormone receptors Interconversion of steroids in target tissues Synthesis and clearance of hormonesDefinition of hormones synthesized and secreted by ductless endocrine glands minute quantities directly into the blood vascular system Classic endocrine glands:pituitary,thyroid,parath

3、yroid,adrenal,pancreas,ovary,testis,placenta,pineal glandDefinition of hormones Reproduction pituitary,pineal glands,gonads,placenta adrenal and thyroid glands uterus,hypothalamusExtra hypothalamic centresHypothalamic centresAnteriorpituritaryGnRHOvaryUterusPinealMelatoninEstrogens/progesteroneFSH/L

4、H Estrogens/progesteroneEstrogensInhibin1.Gonadotropin-releasing hormone2.Gonadotropic hormone3.Sex steroid hormonesChemical classes of reproductive hormones Peptide and protein hormones Releasing hormones,Inhibitory hormones Hypophyseal hormones Neurohypophyseal hormones Placental gonadotropins Sub

5、units Steroid hormones ProstaglandinsThe hormones secreted from the anterior pituitary Peptide and protein hormones Releasing hormones,(GnRH,TRH,CRH,PRH,GH-RH)Peptide hormones produced within the hypothalamus Adenohypophysis Inhibitory hormones Growth hormone(GIH)Prolactin(PIH)portal veinTSH Insulin

6、 ,glucagon Releasing hormones Gonadotropin-releasing hormone(GnRH)pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2(MW of GnRH 1,182)regulate the release of FSH and LHhypothalamic-pituitary-ovarian axis Releasing hormones Thyrotropin-releasing hormone(TRH)pGlu-His-Pro-NH2(MW of TRH 362)regulate the relea

7、se of TSH,GH,and prolactinReleasing hormones Corticotropin-releasing hormone(CRH)CRH is a 41-amino acid peptide regulate the release of ACTHPeptide and protein hormones Hypophyseal hormones Glycoprotein,FSH and LH,prolactin MW of LH 30,000(bovine,ovine,procine,equine)MW of FSH 32,000(ovine,equine)MW

8、 of prolactin 23,000(bovine,ovine,procine)FSH,LH,TSH,ACTH produced in basophilic cells Prolactin localized in acidophilic cells Prolactin Luteotrophic hormone(LTH):a corpus luteum-stimulating effect in mouse,rat,dog and cat 198 a.a,MW 23,300 and a 15-minute half-life in sheep increasing in lactation

9、(mamotropin)stimulating the pigeon crop gland to secret“crop milk”Peptide and protein hormones Neurohypophyseal hormones Oxytocin,Vasopressin(synthesized in hypothalamus)Posterior pituitary releaseAxoplasmic fluidStimulation of the N cellPeptide and protein hormones Placental gonadotropins PMSG(eCG,

10、MW 70,000),a protein hormone in serum,produced by fetal trophoblastic cells of pregnant mares The function of endometrial cups begins on day 36 until 120 days of pregnancy.hCG(MW 36,000),a protein hormone,extracted from the urine of pregnant women from 30-40 days of pregnancy glucocortocoid,estrogen

11、,progestin,relaxinEndometrial cupsEndometrial cups develop from cells of the chorionic girdle,circumferentially around the conceptus at a point where the membranes of the allantois and yolk sac meet.270 days1.The relationship of eCG and CL during equine pregnancy2.eCG has both FSH-like and LH-like a

12、ctivity,it provides the stimulus for the formation of accessory CLs and maintain a plateau of plasma progesterone from about 50-140 days.Clinical use of hCG Athletes use hCG to increase the body natural production of testosterone which is often depressed by long term steroid use.HCG therapy has been

13、 found to be very effective in the prevention of testicular atrophy and to use the body own biochemical stimulating mechanisms to increase plasma testosterone level during training.Clinical use of hCG Peptide and protein hormoneshCGLHhCG-subunit:96 a.a subunit:N-terminal specific for hCGLH-subunit:9

14、6 a.a subunit:119 a.a specific for LHFSH-subunit:96 a.a subunit:specific for FSHTSH-subunit:89 a.a in human subunit:112 a.a in humanPeptide and protein hormones Subunits,-subunit,unique for each hormone within a species,determines the biological activity.Chemical classes of reproductive hormones Ste

15、roid hormones derived from the precursor,cholesterol MW other speciesSynthesis and clearance of hormones PGF2 15-keto-13,14-dihydro-PGF2 Half life primary PGF2 90%excreted in the urine and feces(2:1)over 48 hoursAssay Methods Quantification of specific hormones is necessary for the endocrinological

16、events.Weight-gain change chemical determinations for steroid hormones urine analysisImmunoassay techniqueAgAbAssay Methods Immunoassay Radio-immunoassay(Berson et al.,1959),Sen:10-9 Enzyme multipled immunoassay technique,Sen:10-6 Fluoescine immunoassay,Sen:10-9 EIA(Engvall et al.,1970s),Sen:10-12 C

17、hemiluminescence immunoassay,Sen 10-15RadioimmunoassayBecause of the ease with which iodine atoms can be introduced into tyrosine residues in a protein,the radioactive isotopes 125I or 131I are often used as the radioactive antigen.Sandwich EIAcompetitive EIAsemi quantitative ELISA test The chemical

18、 luminol is oxidised by H2O2,to produce a molecule in an excited state.When the excited electrons in the molecules fall back to their ground states,light is given out.LuminolExcited State Ground State Assay Methods Immunoassay Radio-immunoassay(Berson et al.,1959),Sen:10-9 Competitive protein bindin

19、g EIA(Engvall et al.,1970s),Sen:10-12 Chemiluminescence immunoassay,Sen 10-15Diagnostic aidsTherapy-monitoringNorthern semi-sphereSubtropical TaiwanMonitoring the seasonal estrus activity of marePhysiology of reproductive hormones in the female Estrous cycle Control of the corpus luteum Early pregna

20、ncy Pregnancy and parturitionThe duration of estrus,time of ovulation and duration of CL function in domestic animalsInfluence of the length of day light on the ovary function in maresPhotoreceptors in the eyesPinealHypothalamusAnterior pituitaryOvariesincreasing day lightdecreasing day lightneurotr

21、ansmissionportal systemblood circulationMelatoninMelatoninGnRHGnRHGonadotropineGonadotropineestrous behavior of maresLarge amounts of equine LH are released during an 8-to 9-day period with ovulation occurring on the 3rd to 5th day.Control of the corpus luteum 8-9 days1.theca interna has LH receptor

22、 and produces testosterone.2.granulosa cell has FSH receptor which causes cell to take testosterone from theca and convert it to estradiol.3.dominant follicle has LH receptors on granulosa which can respond to LH to drive progesterone production.P4+feed backLH Ovarian steroidogenesisFSH causes incre

23、ased aromatase activity,which converts testosterone to estradiol Production Rate of Sex Steroids in Women at Different Stages of the Menstrual Cycle DAILY PRODUCTION RATESEX STEROIDS*EarlyFollicular Preovulatory MidlutealProgesterone(mg)142517Hydroxyprogesterone(mg)0.5 4 4 Dehydroepiandrosterone(mg)

24、77 7 Androstenedione(mg)2.64.73.4Testosterone(mg)144 171 126 Estrone(mg)50 350 250 Estradiol(mg)36380250 cumulus cells produce hyaluronic acid and proteins to cause cumulus expansion increased blood flow to follicle(vascular permeability)ovulation Triggers increase protein and steroid synthesis,and

25、cellular differentiation within follicle Plasminogen is converted to plasmin by plasminogen activator(active collagenase).Prostaglandin stimulates smooth muscle to contract and force the ruptured follicle to empty.ovulationControl of the corpus luteum CL is responsible for the estrous cyclicity.Uter

26、us controls the lifespan of the CL in the cow,ewe,sow and mare.Estrogens initiate uterus to synthesizes PGF2.Regression of CL is accomplished within 48 hrs.Control of the corpus luteum Estrogens endometrial oxytocin receptors initiate the release of PGF2,which causes the reaction of luteal regressio

27、n.In ruminants,releasing of PGF2 is induced by oxytocin secreted by the CL.In dog and cat,PGF2 CL?Control of the corpus luteumLH stimulates the secretion of progesterone from small luteal cells while PGF2 inhibits secretion of progesterone from large luteal cells and causes degeneration of these cel

28、ls.Early pregnancy Maternal recognition modification of PGF2 by the luteotropic products from the conceptus and uterus Trophoblast proteins(cow,ewe,doe)Estrogens(sow,mare)intrauterine mobility of the embryo(mare)?(bitch,queen)antiluteolytic action or luteotrophic effect to extend the luteal activity

29、Early pregnancy Trophoblast proteins(cow,ewe,doe)oTP-1 secreted between 10 and 21-24 days bTp-1 secreted between 16-19 days cTP-1 secreted on Day 17 to bind uterine oxytocin receptors to block the uterine PGF2 secretionTrophoblast proteins Ovine trophoblast protein(oTP-1,IFN-)MW 18,000,produced on D

30、ay 10 inhibiting the uterine oxytocin receptors inhibiting the synthesis of PGF2 PGF2,PGE2Early pregnancy Conceptus-derived estrogens(sow,mare)estrone and estradiol 17-converted from progesterone on Day 11,Day14-18 rapid enlongation of the blastocyst releasing of calcium,specific proteins altering a

31、n endocrine of PG to an exocrine PG metabolized to inactive PGFM PGF2 PGE2The secretion of estrogens by the blastocyst stimulates the release of calcium,specific polypeptides and proteins.1.altering the PGF2 from the endocrine to an exocrine2.intrauterine PGF2 metabolised to inactive PGFM by fetal m

32、embranes There is extensive mobility of the equine conceptus within the horns and uterine body before fixation occurs between days 16 and 18.?Endometrial Prostaglandin Synthesis Inhibitor,(EPSI)from endometrium Time of maternal recognition of pregnancy Mare 14-16 36-38Cow 16-17 18-22Sow 12 18Ewe 12-

33、13 16Goat 17Corpus luteum&Pregnancy P4 from CL:cow,sow,goat,dog and cat P4 from CL+fetoplacental unit:mare,sheep Pregnancy1.The sheep placenta produces enough progesterone by day 60-70.2.Luteal progesterone is required throughout gestation in cattle and goats because their placenta secrete much smal

34、ler quantities of progesterone.Fetal-Placental UnitDihydroepiandrosterone Parturition within 12 hoursParturitionProgesterone Fetal hypothalamusFetal pituitaryFetal adrenalCotyledons/myometriumMyometrial contractionsPosterior pituitaryFetalmaturationDecrease in placental P4Luteolysis of the CL of pre

35、gnancyDecrease in serum P4Increased myometrialexcitabilityAdrenalineRelaxation and softening of cervix pelvic ligaments,perineumRelaxin?Expulsion of fetusStimulates vagina and cervixAbdominal strainingParturition Prostaglandins are soluble in fat and water,Prostaglandins pass from cell to cell Actio

36、ns:smooth muscle contraction luteolysis softening of cervical collagen developing gap junctions movement of Ca2+between the myofibrils PGF2,PGE,PGI2Smooth muscle contraction Muscle protein:myosin and actin Calmodulin activates MLC kinaseCalcium-CalmodulinMLC kinaseinactive myosin light chaincontract

37、ions actomyosin complex(M*-ATP)+A (M*-ADP-A)+Pi(M*-ADP-A)(M-A)+ADP The top view shows a relaxed smooth muscle cell.Note the focal densities and the network of actin and myosin filaments.When contracted,the filaments slide together and pull the cell to a more rounded appearance.Smooth muscle contract

38、ionCalmodulin is one of the primary receptors of intracellular calcium.4 Ca2+bind to calmodulin.At each binding site,Ca interacts with oxygen atoms,mainly glutamate and aspartase side-chain carboxyl group.Calmodulin mediates processes such as inflammation,metabolism,apoptosis,muscle contraction,nerv

39、e growth,immune response.Parturition Actions of estrogens contractile protein synthesis receptors of oxytocin and PGF2 calmodulin synthesis MLC kinase activity gap junctions Parturition Actions of progesterone gap junctions receptors of oxytocin and PGF2 synthesis of oxytocin and PGF2 calmodulin bin

40、dingParturition Actions of oxytocin dependent on progesterone,estrogens stimulation of receptors in the anterior vagina and cervix oxytocin release increasing PG release increasing Ca2+releaseClinical aspects of reproductive endocrinology Steroid hormone concentrations are lower in animals than in h

41、uman.(estrogens 1/10)Progesterone analysis give the most useful information on the reproductive status.Blood,milk,urine,saliva and feces are sources for endocrine information.Cow:P4 for early diagnosis of pregnancy Negative forecast(98%)is better than positive forecast(67-90%).P4 for postpartum ovar

42、ian activity Estrone sulfate for diagnosis of pregnancy from Day 120,96%accuracy rate Bovine pregnancy specific protein B for early diagnosis of pregnancy on Day 30Clinical aspects of reproductive endocrinologyP4 for postpartum ovarian activity or early diagnosis of pregnancySampling timeFollicular

43、cystOvarian cystP4 for postpartum ovarian activityP4 for postpartum ovarian activityLuteal cystNormal cycleSampling timeSampling timeSampling timePersistent CL or luteal cystOvarian atrophy or follicular cystDiagnosis of the ovarian diseases in cattle GnRH HypothalamusHypophyseLHProgesteroneRegulati

44、on of estrus cycleTreatment of bovine follicular cystovulation stimulation or cyst luteinization or ovulation of cyst Monitoring the treatment of bovine follicular cystGnRH inj.PGF2 inj.AIGnRH inj.Sampling timeSampling timeSampling timeClinical aspects of reproductive endocrinology Sheep:P4 for earl

45、y diagnosis of pregnancy P4 in estrus:0.15-0.25 ng/ml,in CL phase:2-4 ng/ml,in pregnancy from 60 days:12-20 ng/ml Estrone sulfate(fetoplacenta)for diagnosis of pregnancy from 70 days(88%)Pregnancy specific protein,ovine placental lactogen for diagnosis of pregnancyClinical aspects of reproductive en

46、docrinology Sow:P4 for early diagnosis of pregnancy P4 in pregnancy:20-50 ng/ml Estrone sulfate for early diagnosis of pregnancy from Day 20-26,98%accuracy rate Clinical aspects of reproductive endocrinology Horse:eCG for diagnosis of pregnancy P4 for ovarian activity Persistent CL exhibits low P4 v

47、alue Presence of cyclic ovarian activity Ovulation prediction(88%)Estrone sulfate for diagnosis of pregnancy Testosterone for diagnosis of granulosa cell tumor,cryptorchidism Dog:P4 for preovulatory breeding P4 for diagnosis of remaining ovarian remnant Testosterone for checking the secretory status

48、 of the Ledig cells Confirmation of sertoli cell tumors:LH,T(Cryptorchidism)Relaxin for confirmation of pregnancy status Cat:P4 for confirmation of ovulatory failure,P410 days postbreeding(P4 0.15 ng/ml)Estrogen analysis(from feces)for ovarian follicular activity,completeness of an OHE Testosterone

49、for evaluation of Ledig cell function in the testis Relaxin for confirmation of pregnancy statusGeneral comments Reference values developed by laboratories are depend on the type of assay used.1 ng/ml as the basal value of P4 Harvesting serum soon after collection RBC can metabolize P4 to other steroids Temperature,P4 decline slowly Skim milk for the immunoassay of P4contraceptionDry