Bibliography: leaves 230-294. / xiii, 294 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Analyses in detail a native small fragment of hCG/[beta] hCG subunit, the [beta]-core hCG fragment which is found in large amounts in urine and may be of clinical importance. The aims were to purify the fragment, analyse its protein and carbohydrate structure, develop direct assay methods for its measurement, and to examine it's distribution in body fluids and it's relationship with the intact hCG molecule during pregnancy. / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1993

Human chorionic gonodotropin (HCG) affected in various ways cell cultures infected with strains of Rous sarcoma virus (RSV). The cell cultures studied were chick embryo fibroblasts (CEF), normal rat kidney cells infected with temperature-sensitive mutant (LA31-NRK) and a wild type RSV (B77-NRK). HCG increased the rate of transformation and viral titer of CEF cells infected with RSV, but not B77-NRK. HCG increased significantly transformation rates of LA31-NRK, only if the temperature sensitive transformation process was first delayed by incubation at non-permissive temperatures. It is suggested that some postinfective, pretransformational event(s) may operate before viralmediated transformation rates are increased by HCG.

Orientador: Guilherme de Paula Nogueira / Banca: Ed Hoffmann Madureira / Banca: Ciro Moraes Barros / Resumo: Avaliou-se a secreção de LHe FSH de plasmático em novilhasdurantea exposição à diferentes concentrações de progesterona(P4) e após a administração deGnRH ou benzoatodeestradiol (BE). Novenovilhas Nelore, pré-sincronizadas com PgF2a, emintervalo de 12 dias, foram submetidas a 6protocolos comrepetições casualizadas. Os 3 grupos de P4foram: CL (Corpo Lúteo), IMPL+CL (DIB® ecorpo lúteo) e IMPL(DIB®), eapós a remoçãodaP4 estimuladascom GnRH ou BE. Durante a P4, foicoletado sangue a cada12h e nos dias 3, 4 e 5 acada 15 min durante 6 h em 1 animalde cada grupo, depois da retiradados implantes e/ou aplicação de PgF2a, coletas foramrealizadas a cada 3hpor 24 h (BE) ou a cadahora por10h (GnRH) para quantificação de LH e FSH. O exame ultrasonográfico foi realizado a cada 12 he após o términodascoletas de sangue às 24h e 48h. Às 12 h após colocação do implante, o grupo IMPL+CLapresentou menorconcentração de LHque o grupo IMPL,após 36 h os grupos IMPL+C e IMPL apresentaram menorconcentração de LH que o grupo CL e às 60 h o grupo IMPL apresentou menor secreção que o grupo CL. Após 24 h da colocação dos implantes, o grupo IMPL apresentou maior secreção de FSH que os demais grupos, e após 48 e 60 h o grupo IMPL+CL apresentou maior secreção de FSH que o grupo CL. No grupo IMPL, a amplitude máxima do pico de LH foi maior após o GnRH quando comparado com o BE. No grupo CL as novilhas apresentaram menor número de folículos ovarianos e maior diâmetro do maior folículo em relação aos grupos IMPL+CL e IMPL. Quando foi aplicado BE, o grupo IMPL+CL apresentou menor taxa de ovulação com 24 h que os grupos CL e IMPL. Os protocolos de sincronização da ovulação empregados foram ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The LH and FSH secretion and follicle profile was evaluated during expositionto different progesterone (P4) concentration and afterGnRH or estradiol benzoate (BE) administration inNelore heifers. Nine heifers were pré-sinchronized with PGF2a (two injection with 12 days interval) received 6 treatments randomly repeated . There were 3 P4 groups: CL (corpus luteum), IMPL+CL (DIB®and CL) and IMPL (DIB®)that were stimulatedwith GnRH or BE after P4 removal. During P4 blood samples were collected every12 hand on days 3, 4and 5 every 15 minfor 6 hfrom 1 animal per group, after P4 device removal, every 3 hfor 24 h (BE)orevery hour for 10 h(GnRH), for LH and FSH quantification. Ultrasound examination was realizedevery 12 h until the end of blood samples, andthereafter 24 and 48 h. At 12hafter implant insertion the IMPL+CLgroup presented lower LH concentration than IMPL group, after 36 hthe animals with implant presented lower LH concentration than CL group, and after 60h the IMPL group had lower LH secretionthan CL one. On IMPL group,themaximum LH peak amplitude was higher in animalsthat received GnRH comparedto BE. Group with CL presented fewer follicles and higher largest follicle diameterthan IMPL+CLand IMPL. When BE was injected the IMPL+CL group presented lower ovulation rateat 24 h than CL and IMPLgroups. The ovulation synchronization protocols used wereefficient in promoting a preovulatory LH peak in Neloreheifers, independentlyof an associated CL or not to progesterone device. The GnRH treatment induced a higher LH peak amplitude and with an higer efficiency in stimulating ovulation in 24h than BE treatment, in animals with higher progesterone...(Complete abstract, click electronic access below) / Mestre

Yam Kwan Mei. / Thesis submitted in: August 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 108-129). / Abstracts in English and Chinese. / Abstract (in English) --- p.ii / Abstract (in Chinese) --- p.iv / Acknowledgement --- p.vi / Table of Contents --- p.ix / List of Tables --- p.xiv / List of Figures --- p.xv / Symbols and Abbreviations --- p.xviii / Scientific names --- p.xx / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Gonadotropins --- p.1 / Chapter 1.1.1 --- Structure --- p.1 / Chapter 1.1.2 --- Function --- p.3 / Chapter 1.1.3 --- Regulation --- p.9 / Chapter 1.1.3.1 --- GnRH --- p.9 / Chapter 1.1.3.2 --- Steroids --- p.11 / Chapter 1.1.3.3 --- Activin --- p.12 / Chapter 1.2 --- Activin Family of Growth Factors --- p.14 / Chapter 1.2.1 --- Structure --- p.14 / Chapter 1.2.2 --- Function --- p.17 / Chapter 1.3 --- Objectives --- p.22 / Chapter Chapter 2 --- Cloning of Goldfish Activin βA cDNA and the Expression of Its mRNA in Gonadal and Non-gonadal Tissues --- p.24 / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Materials and Methods --- p.25 / Chapter 2.2.1 --- Cloning of goldfish activin βA cDNA --- p.26 / Chapter 2.2.1.1 --- Cloning of the 5' and 3' cDNA ends --- p.26 / Chapter 2.2.1.2 --- Extension of the 5' and 3' fragments --- p.28 / Chapter 2.2.2 --- Sequencing of the cDNA --- p.28 / Chapter 2.2.2.1 --- Generation of pKS/GactβA constructs with insert in different orientations --- p.28 / Chapter 2.2.2.2 --- Generation of overlapping subclones --- p.29 / Chapter 2.2.2.3 --- Cycle sequencing --- p.30 / Chapter 2.2.2.4 --- Sequence analyses --- p.30 / Chapter 2.2.3 --- Isolation of total and messenger RNA --- p.30 / Chapter 2.2.3.1 --- Isolation of total RNA --- p.30 / Chapter 2.2.3.2 --- Isolation of messenger RNA --- p.31 / Chapter 2.2.4 --- Southern blot analysis --- p.32 / Chapter 2.2.5 --- Northern blot analysis --- p.33 / Chapter 2.2.6 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.33 / Chapter 2.3 --- Results --- p.35 / Chapter 2.3.1 --- Cloning and sequence analysis of activin β A cDNA --- p.35 / Chapter 2.3.2 --- Distribution of activin βA mRNA in different tissues --- p.49 / Chapter 2.4 --- Discussion --- p.53 / Chapter Chapter 3 --- Establishment and Characterization of Stable Cell Lines for the Recombinant Production of Goldfish Activin A --- p.59 / Chapter 3.1 --- Introduction --- p.59 / Chapter 3.2 --- Materials and Methods --- p.60 / Chapter 3.2.1 --- Construction of expression plasmid --- p.60 / Chapter 3.2.2 --- Cell culture --- p.62 / Chapter 3.2.3 --- Transfection of CHO cells --- p.62 / Chapter 3.2.4 --- G418 selection of transfected CHO cells --- p.62 / Chapter 3.2.5 --- Activin bioassay (EDF-assay) --- p.63 / Chapter 3.2.6 --- Cloning of pBK/GactβA-transfected CHO cells by limited dilution --- p.63 / Chapter 3.2.7 --- Isolation of total RNA --- p.65 / Chapter 3.2.8 --- Northern blot analysis --- p.65 / Chapter 3.3 --- Results --- p.66 / Chapter 3.3.1 --- Optimization of G418 concentration for selection --- p.66 / Chapter 3.3.2 --- Expression of activin activity by pBK/GactpβA- transfected CHO cells --- p.67 / Chapter 3.3.3 --- Establishment and characterization of CHO cell lines that stably produce recombinant goldfish activin A --- p.67 / Chapter 3.4 --- Discussion --- p.73 / Chapter Chapter 4 --- Differential Regulation of Goldfish Gonadotropin (GTH-Iβ and GTH-IIβ) Gene Expression by Recombinant Goldfish Activin --- p.79 / Chapter 4.1 --- Introduction --- p.79 / Chapter 4.2 --- Materials and Methods --- p.82 / Chapter 4.2.1 --- Animals --- p.82 / Chapter 4.2.2 --- Drug treatment --- p.83 / Chapter 4.2.3 --- Primary culture of dispersed pituitary cells --- p.84 / Chapter 4.2.4 --- Southern blot analysis --- p.85 / Chapter 4.2.5 --- Isolation of total RNA --- p.86 / Chapter 4.2.6 --- Northern blot analysis --- p.86 / Chapter 4.2.7 --- Dot blot analysis --- p.87 / Chapter 4.2.8 --- Data analyses --- p.87 / Chapter 4.3 --- Results --- p.88 / Chapter 4.3.1 --- Probe specificity --- p.88 / Chapter 4.3.2 --- Effects of goldfish activin on pituitary GTH-Iβ and -IIβ mRNA expression --- p.88 / Chapter 4.3.3 --- Blockade of activin effects by follistatin --- p.92 / Chapter 4.4 --- Discussion --- p.96 / Chapter Chapter 5 --- General Discussion --- p.101 / Chapter 5.1 --- Overview --- p.101 / Chapter 5.2 --- Contribution of the Present Research --- p.103 / Chapter 5.2.1 --- Cloning of full-length goldfish activin βA cDNA --- p.103 / Chapter 5.2.2 --- Establishment of stable cell lines for the recombinant production of goldfish activin A --- p.104 / Chapter 5.2.3 --- Differential regulation of goldfish gonadotropin (GTH-Iβ and GTH-IIβ) gene expression by recombinant goldfish activin --- p.105 / Chapter 5.3 --- Future Research Direction --- p.107 / Chapter 5.3.1 --- Activin studies --- p.107 / Chapter 5.3.2 --- Gonadotropin studies --- p.107 / References --- p.108

Kwok Hin-Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 84-100). / Abstracts in English and Chinese. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgement --- p.vi / Table of contents --- p.vii / List of figures --- p.xi / List of tables --- p.xiv / Symbols and abbreviations --- p.xv / List of fish names mentioned in the thesis --- p.xviii / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Gonadotropins / Chapter 1.1.1 --- Structure --- p.1 / Chapter 1.1.2 --- Function --- p.4 / Chapter 1.2 --- Gonadotropin receptor / Chapter 1.2.1 --- Structure --- p.5 / Chapter 1.2.2 --- Expression --- p.7 / Chapter 1.2.3 --- Signaling / Chapter 1.2.3.1 --- cAMP-mediated pathway --- p.7 / Chapter 1.2.3.2 --- Phospholipase C-mediated pathway --- p.9 / Chapter 1.2.4 --- Regulation of expression --- p.12 / Chapter 1.2.5 --- Desensitization of receptors / Chapter 1.2.5.1 --- Uncoupling --- p.13 / Chapter 1.2.5.2 --- Internalization --- p.13 / Chapter 1.3 --- Structure of ovarian follicles --- p.14 / Chapter 1.4 --- The project objectives and long-term significance --- p.16 / Chapter Chapter 2 --- Cloning and Characterization of Zebrafish Follicle-stimulating Hormone (FSH) and Luteinizing Hormone (LH) Receptors ´ؤ Evidence for Distinct Functions of FSH and LH in Follicle Development / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Materials and Methods / Chapter 2.2.1 --- Animals and chemicals --- p.22 / Chapter 2.2.2 --- Isolation of total RNA --- p.22 / Chapter 2.2.3 --- Cloning of zebrafish FSHR (zfFSHR) and LHR (zfLHR) cDNA fragments from the zebrafish ovary --- p.23 / Chapter 2.2.4 --- Rapid amplification of 5´ةcDNA ends (5'-RACE) and full-length cDNA --- p.24 / Chapter 2.2.5 --- Isolation of ovarian follicles --- p.25 / Chapter 2.2.6 --- Sampling of the ovaries from sexually immature zebrafish --- p.25 / Chapter 2.2.7 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.25 / Chapter 2.2.8 --- Construction of expression plasmids --- p.26 / Chapter 2.2.9 --- Transient transfection and reporter gene assay --- p.27 / Chapter 2.2.10 --- Establishment and characterization of stable zfFSHR or zfLHR-expressing cell lines --- p.28 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Cloning of FSHR and LHR cDNA from the zebrafish ovary --- p.29 / Chapter 2.3.2 --- Functional characterization of zfFSHR and zfLHR --- p.30 / Chapter 2.3.3 --- Expression of zfFSHR and zfLHR during sexual maturation --- p.31 / Chapter 2.3.4 --- Stage-dependent expression of zfFSHR and zfLHR in the ovarian follicles --- p.32 / Chapter 2.4 --- Discussion --- p.33 / Chapter Chapter 3 --- Down-regulation of FSHR and LHR Expression in the Zebrafish Follicle Ceils by Gonadotropin (hCG) and Its Sigaling Mechanism / Chapter 3.1 --- Introduction --- p.51 / Chapter 3.2 --- Materials and Methods / Chapter 3.2.1 --- Animals --- p.54 / Chapter 3.2.2 --- Chemicals and hormones --- p.54 / Chapter 3.2.3 --- Primary follicle cell culture --- p.55 / Chapter 3.2.4 --- Total RNA isolation --- p.55 / Chapter 3.2.5 --- "Validation of semi-quantitative RT-PCR assays for FSHR, LHR and GAPDH" --- p.56 / Chapter 3.2.6 --- Data analysis --- p.57 / Chapter 3.3 --- Results / Chapter 3.3.1 --- Validation of semi-quantitative RT-PCR assays --- p.57 / Chapter 3.3.2 --- Gonadotropin regulation of FSHR and LHR expression in cultured zebrafish ovarian follicle cells --- p.58 / Chapter 3.3.3 --- Effect of db-cAMP and forskolin on FSHR and LHR expression --- p.59 / Chapter 3.3.4 --- Effects of H89 on hCG-induced suppression of FSHR and LHR expression --- p.60 / Chapter 3.4 --- Discussion --- p.60 / Chapter Chapter 4 --- General Discussion --- p.75 / Chapter 4.1 --- Cloning of zebrafish FSHR and LHR cDNAs and demonstration of receptor specificity --- p.77 / Chapter 4.2 --- Evidence for the differential expression of FSHR and LHR in the zebrafish ovarian and follicle development --- p.78 / Chapter 4.3 --- Down-regulation of FSHR and LHR expression in the zebrafish follicle cells by gonadotropin (hCG) --- p.79 / Chapter 4.4 --- Future research direction --- p.80 / References --- p.84

So Wai-Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 100-127). / Abstracts in English and Chinese. / Acknowledgement --- p.I / Abstract (in English) --- p.II / Abstract (in Chinese) --- p.IV / Table of contents --- p.VI / List of Figures --- p.X / Symbols and Abbreviations --- p.XII / List of fish names mentioned in the thesis --- p.XIV / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Pituitary --- p.1 / Chapter 1.2 --- Gonadotropins --- p.1 / Chapter 1.2.1 --- Structure --- p.2 / Chapter 1.2.2 --- Signaling --- p.3 / Chapter 1.2.3 --- Expression --- p.5 / Chapter 1.2.4 --- Functions --- p.7 / Chapter 1.2.4.1 --- Gonadotropin actions on gametogenesis --- p.7 / Chapter 1.2.4.2 --- Gonadotropin actions on steroidogenesis --- p.8 / Chapter 1.2.5 --- Regulation --- p.9 / Chapter 1.2.5.1 --- Neuroendocrine control --- p.10 / Chapter 1.2.5.1.1 --- Gonadotropin-releasing hormone (GnRH) --- p.10 / Chapter 1.2.5.1.2 --- Dopamine (DA) --- p.12 / Chapter 1.2.5.2 --- Gonadal steroid feedback --- p.12 / Chapter 1.2.5.2.1 --- Positive feedback --- p.13 / Chapter 1.2.5.2.2 --- Negative feedback --- p.14 / Chapter 1.2.5.3 --- Paracrine regulators within pituitary --- p.15 / Chapter 1.3 --- Objectives of the present study --- p.16 / Chapter Chapter 2 --- "Molecular Cloning and Functional Characterization of Zebrafish FSHβ, LHβ and GTHα subunits" / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Materials and methods --- p.21 / Chapter 2.2.1 --- Chemicals --- p.21 / Chapter 2.2.2 --- Animals --- p.21 / Chapter 2.2.3 --- Genomic DNA isolation --- p.22 / Chapter 2.2.4 --- Total RNA isolation --- p.22 / Chapter 2.2.5 --- Cloning of zebrafish FSHp，LHβ and GTHa fragments --- p.23 / Chapter 2.2.5.1 --- LHβ and GTHα --- p.23 / Chapter 2.2.5.2 --- FSHβ --- p.23 / Chapter 2.2.6 --- "5'- and 3'-RACE of zebrafish FSHp, LHβ and GTHα subunits" --- p.24 / Chapter 2.2.7 --- Construction of expression constructs --- p.25 / Chapter 2.2.8 --- Cell culture and transfection of Flp-In´ёØ CHO cell --- p.26 / Chapter 2.2.9 --- Recombinant production of zebrafish FSH and LH --- p.27 / Chapter 2.2.10 --- Reverse transcription-polymerase chain reaction (RT-PCR) analysis --- p.27 / Chapter 2.2.11 --- Northern blot hybridization --- p.28 / Chapter 2.2.12 --- SEAP reporter gene assay --- p.28 / Chapter 2.2.13 --- Data analysis --- p.29 / Chapter 2.3 --- Results --- p.30 / Chapter 2.3.1 --- "Cloning of zebrafish FSHβ, LHβ and GTHα subunits" --- p.30 / Chapter 2.3.2 --- "Expression of zebrafish FSHp, LHβ and GTHα in the zebrafish pituitary" --- p.31 / Chapter 2.3.3 --- Recombinant production of zebrafish FSH and LH --- p.32 / Chapter 2.3.4 --- Functional analysis of zebrafish FSH and LH --- p.33 / Chapter 2.4 --- Discussion --- p.34 / Chapter Chapter 3 --- "Spatial Expression Patterns of Zebrafish FSHβ, LHβ and GTHα Subunits in the Pituitary and Their Temporal Expression Profiles during Sexual Maturation and Ovulatory Cycle" / Chapter 3.1 --- Introduction --- p.58 / Chapter 3.2 --- Materials and methods --- p.61 / Chapter 3.2.1 --- Chemicals --- p.61 / Chapter 3.2.2. --- Animals --- p.62 / Chapter 3.2.3 --- Total RNA isolation from zebrafish pituitaries and reverse transcription --- p.62 / Chapter 3.2.4 --- Validation of RT-PCR on single pituitary --- p.63 / Chapter 3.2.5 --- Real-time PCR --- p.64 / Chapter 3.2.6 --- Tissue preparation for in situ hybridization --- p.64 / Chapter 3.2.7 --- In situ hybridization --- p.65 / Chapter 3.2.8 --- Data analysis --- p.66 / Chapter 3.3 --- Results --- p.66 / Chapter 3.3.1 --- "PCR amplification of FSHβ, LHβ and GTHα and GAPDH in single zebrafish pituitary" --- p.67 / Chapter 3.3.2 --- "Establishement of real-time RT-PCR for zebrafish FSHβ, LHβ and GTHa and GAPDH" --- p.67 / Chapter 3.3.3 --- "Temporal expression profiles of zebrafish FSHβ, LHβ and GTHα subunits during sexual maturation" --- p.67 / Chapter 3.3.4 --- "Temporal expression profiles of zebrafish FSHp, LHβ and GTHα subunits during ovulatory cycle" --- p.68 / Chapter 3.3.5 --- "In situ hybridization of zebrafish FSHβ, LHβ and GTHα" --- p.69 / Chapter 3.4 --- Discussion --- p.70 / Chapter Chapter 4 --- General Discussion / Chapter 4.1 --- Cloning of zebrafish gonadotropin subunit cDNAs --- p.91 / Chapter 4.2 --- Bioactivity and receptor specificity of recombinant zebrafish FSH and LH --- p.91 / Chapter 4.3 --- Expression of gonadotropin subunits during zebrafish sexual maturation and ovulatory cycle --- p.92 / Chapter 4.4 --- "Localization of FSHβ, LHβ and GTHα subunits in zebrafish pituitary" --- p.93 / Chapter 4.5 --- Contributions of the present study --- p.94 / Chapter 4.6 --- Future prospects --- p.95 / References --- p.100

A series of experiments was conducted to evaluate the effects of nutrition during calfhood (defined as the period from 10 to 26-30 wk of age) and peripubertal period (defined as the period from 27-31 to 70-74 wk of age) on sexual development and reproductive function in beef bulls. The overall objective of these experiments was to evaluate the effects of nutrition on endogenous metabolic hormones (leptin, insulin, GH, and IGF-I), gonadotropins and testosterone concentrations, sexual development, sperm production, and semen quality in bulls. The results of these experiments demonstrated that nutrition affected GnRH secretion and sexual development in bulls. Increased nutrition during calfhood resulted in a more sustained increase in LH pulse frequency during the early gonadotropin rise and greater testicular development at maturity. On the other hand, low nutrition during calfhood suppressed LH secretion during the early gonadotropin rise and resulted in delayed puberty and reduced testicular development at maturity. When low nutrition was accomplished by restricted feed intake, hypothalamic and pituitary function were compromised and LH secretion was more severely affected. Temporal associations between LH secretion patterns and circulating IGF-I concentrations implied that IGF-I is a possible signal to the central metabolic sensor involved in translating body nutritional status to the GnRH pulse generator. Nutrition also affected testicular steroidogenesis (testosterone concentrations), indicating effects on the number or function of Leydig cells, or both. Age-related increases in physiological and GnRH-stimulated circulating testosterone concentrations were hastened in bulls receiving high nutrition and delayed in bulls receiving low nutrition; these effects were probably mediated by both LH secretion and IGF-I concentrations. Circulating leptin and insulin may have only permissive roles on GnRH secretion, but may enhance testicular development. Growth hormone concentrations decreased concomitantly with increasing IGF-I concentrations during sexual development in bulls, suggesting that the testes could contribute considerable amounts of circulating IGF-I. In conclusion, management strategies to optimize reproductive function in bulls should focus on increasing nutrition during calfhood.

A series of experiments was conducted to evaluate the effects of nutrition during calfhood (defined as the period from 10 to 26-30 wk of age) and peripubertal period (defined as the period from 27-31 to 70-74 wk of age) on sexual development and reproductive function in beef bulls. The overall objective of these experiments was to evaluate the effects of nutrition on endogenous metabolic hormones (leptin, insulin, GH, and IGF-I), gonadotropins and testosterone concentrations, sexual development, sperm production, and semen quality in bulls. The results of these experiments demonstrated that nutrition affected GnRH secretion and sexual development in bulls. Increased nutrition during calfhood resulted in a more sustained increase in LH pulse frequency during the early gonadotropin rise and greater testicular development at maturity. On the other hand, low nutrition during calfhood suppressed LH secretion during the early gonadotropin rise and resulted in delayed puberty and reduced testicular development at maturity. When low nutrition was accomplished by restricted feed intake, hypothalamic and pituitary function were compromised and LH secretion was more severely affected. Temporal associations between LH secretion patterns and circulating IGF-I concentrations implied that IGF-I is a possible signal to the central metabolic sensor involved in translating body nutritional status to the GnRH pulse generator. Nutrition also affected testicular steroidogenesis (testosterone concentrations), indicating effects on the number or function of Leydig cells, or both. Age-related increases in physiological and GnRH-stimulated circulating testosterone concentrations were hastened in bulls receiving high nutrition and delayed in bulls receiving low nutrition; these effects were probably mediated by both LH secretion and IGF-I concentrations. Circulating leptin and insulin may have only permissive roles on GnRH secretion, but may enhance testicular development. Growth hormone concentrations decreased concomitantly with increasing IGF-I concentrations during sexual development in bulls, suggesting that the testes could contribute considerable amounts of circulating IGF-I. In conclusion, management strategies to optimize reproductive function in bulls should focus on increasing nutrition during calfhood.

The present investigation was designed to further our understanding of the interaction of pituitary (luteinizing hormone, LH) and placental (chorionic gonadotropin, CG) gonadotropins with the primate corpus luteum. Studies were performed (1) to characterize the LH/CG receptor population in the

RATIONALE OF THE STUDY. To carry out a retrospective chart review of all patients who had a peripartum hysterectomy in hospitals at different levels of health care in the Pietermaritzburg Hospital Complex to examine the incidence and indications for peripartum hysterectomy. METHODS. The charts of 120 cases of peripartum hysterectomy operations performed between January 2003 and January 2008 in the Pietermaritzburg hospital complex of University of KZN were analysed retrospectively. The total number of deliveries were 48 964. The traditional indications, risk factors and associated complications were revisited to determine if there have been changes in current obstetric practice. RESULTS. The overall incidence of peripartum hysterectomy at the Pietermaritzburg complex of hospital was 0.25/1000 deliveries (95% C1 0.2 – 2.9). Uterine atony, bleeding abruption placentae, placentae praevia, uterine rupture following induction and extension of uterine incision into the uterine arteries comprised 87.9% of the indications for peripartum hysterectomy. By far, the most common complications were wound infection and haemorrhage due to difficult haemostasis. Both comprised 61% of complications, others were bladder injury and renal failure. Coagulopathy occurred in 16.7% of cases of whom 2 died due to massive uncontrollable haemorrhage and 26.7% cases had relaparatomy. There were 13.3% of haemorrhagic shock and 5% developed septic shock. All the patients had blood transfusion, 13.3% of patients received platelets in addition to blood. The results showed that 55.8% had previous caesarean sections while 12.5% had VBAC. There were 75.8% live babies. CONCLUSION. The review noted that there has not been a significant change in the incidence and indications for peripartum hysterectomy. The incidence of peripartum hysterectomy in the study 0.25/1000 compared favourably with the findings from similar studies in different parts of the world. Worldwide the incidence of PH ranges from 0.2 to 5.09/1000 deliveries, in our study the incidence was 0.25/1000. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2012.