Bayesian estimation of sensitivity and specificity of a milk pregnancy-associated glycoprotein ELISA test for pregnancy diagnosis between 23 and 27 days after insemination in Holstein dairy cows.

Pregnancy diagnosis using pregnancy-associated glycoprotein (PAG) ELISA technology in blood or milk samples is validated from 28 d after insemination in dairy cows. The objective of this study was to estimate the sensitivity (Se) and specificity (Sp) of a commercial milk PAG-based ELISA in Holstein dairy cows between 23 and 27 d after insemination. Milk samples (n = 268) from 257 Holstein dairy cows 23 to 27 d after AI were submitted for PAG ELISA testing. Pregnancy status was confirmed by either a second milk PAG ELISA test conducted between 28 and 50 d after insemination (n = 200) or transrectal ultrasonography performed between 28 and 59 d after insemination (n = 68). A Bayesian latent class model was used to compare the paired results from the test at 23 to 27 d after AI test to the reference test. The latent class model typically used for comparing 2 or more imperfect tests was extended to include the possibility of pregnancy loss between the 23 to 27 d test and the reference test. Informative priors for the probability of pregnancy loss, and for the Se and Sp of the PAG and ultrasonography reference tests were obtained from the scientific literature. Estimated median Se and Sp of the PAG ELISA test conducted between 23 and 27 d after AI were 0.98 (95% credible interval 0.93 to 1.0) and 0.98 (0.89 to 1.0), respectively, when using a standardized corrected optical density threshold of 0.15. Although the accuracy of the test under investigation was excellent, more data will be needed to confirm the optimal diagnostic cut point for PAG in milk for early pregnancy diagnosis in this time window. The optimal timing of pregnancy diagnosis will depend on herd-specific logistics and the action to be taken to re-inseminate nonpregnant cows.

E-therapies in England for stress, anxiety or depression: what is being used in the NHS? A survey of mental health services.

OBJECTIVE: To document the range of web and smartphone apps used and recommended for stress, anxiety or depression by the National Health Service (NHS) in England. DESIGN: The study was conducted using Freedom of Information (FOI) requests and systematic website searches. DATA SOURCES: Data were collected via FOI requests to NHS services between 13 February 2015 and 31 March 2015, and searches conducted on NHS apps library websites between 26 March 2015 and 2 November 2015. DATA COLLECTION/EXTRACTION METHODS: Data were compiled from responses to: (1) FOI requests sent to all Improving Access to Psychological Therapies (IAPT) services and NHS Mental Health Trusts in England and (2) NHS apps library search results. RESULTS: A total of 61 (54.95%) out of the then 111 IAPT service providers responded, accounting for 191 IAPT services, and all 51 of the then NHS Mental Health Trusts responded. The results were that 13 different web apps and 35 different smartphone apps for depression, anxiety or stress were available through either referral services or the online NHS Apps Libraries. The apps used and recommended vary by area and by point of access (online library/IAPT/trust). CONCLUSIONS: Future research is required to establish the evidence base for the apps that are being used in the NHS in England. There is a need for service provision to be based on evidence and established guidelines.

Prevalence of elevated milk ß-hydroxybutyrate concentrations in Holstein cows measured by Fourier-transform infrared analysis in Dairy Herd Improvement milk samples and association with milk yield and components.

The purpose was to describe the prevalence and effect of elevated milk ß-hydroxybutyrate (BHB) as detected by routine Fourier-transform infrared analysis in Dairy Herd Improvement milk samples. Data collected over 4 yr included cow information as well as milk yield and composition from 498,310 samples from postparturient Holstein cows (5-35d in milk) from 4,242 herds. The following thresholds were used to classify cows based on their early lactation milk BHB concentration: <0.15mmol/L=negative; 0.15 to 0.19mmol/L=suspect; and ≥0.20mmol/L=positive. Overall prevalence (suspect + positive) was 22.6% and was higher for older cows (18.7, 19.5, and 27.6%, for cows in their first, second, and third or greater lactation, respectively). Distribution with regards to days in milk was different among parity groups, with first-lactation cows having highest prevalence (30%) in the first week after calving; cows in their second and third and greater parity had the highest prevalence in the second week after calving, at 25.8 and 34.6%, respectively. Season of calving affected the prevalence of elevated milk BHB, with cows calving in the fall and spring seasons showing higher prevalence. Distribution among herds was highly variable, as 45% of herds had a prevalence of 20% or less, 47% of herds had a prevalence between 21 and 40%, 6% of herds had a prevalence between 40 and 50%, and 2% of herds had a prevalence of 50% or above. Positive cows had lower milk yield, protein concentration and yield, and lower Transition Cow Index than negative cows, but also higher fat concentration and yield, as well as higher somatic cell count than negative cows. Suspect cows were generally intermediate. The present analysis highlights the opportunity for elevated milk BHB monitoring at the herd level through routine BHB testing in Dairy Herd Improvement milk samples.

Genetic analysis of milk ß-hydroxybutyrate and its association with fat-to-protein ratio, body condition score, clinical ketosis, and displaced abomasum in early first lactation of Canadian Holsteins.

The aim of this study was to estimate genetic parameters for milk ß-hydroxybutyrate (BHBA) in early first lactation of Canadian Holstein cows and to examine its genetic association with indicators of energy balance (fat-to-protein ratio and body condition score) and metabolic diseases (clinical ketosis and displaced abomasum). Data for milk BHBA recorded between 5 and 100 d in milk was obtained from Valacta (Sainte-Anne-de-Bellevue, Québec, Canada), the Canadian Dairy Herd Improvement organization responsible for Québec and Atlantic provinces. Test-day milk samples were analyzed by mid-infrared spectrometry using previously developed calibration equations for milk BHBA. Test-day records of fat-to-protein ratio were obtained from the routine milk recording scheme. Body condition score records were available from the routine type classification system. Data on clinical ketosis and displaced abomasum recorded by producers were available from the national dairy cattle health system in Canada. Data were analyzed using linear animal models. Heritability estimates for milk BHBA at different stages of early lactation were between 0.14 and 0.29. Genetic correlations between milk BHBA were higher between adjacent lactation intervals and decreased as intervals were further apart. Correlations between breeding values for milk BHBA and routinely evaluated traits revealed that selection for lower milk BHBA in early lactation would lead to an improvement of several health and fertility traits, including SCS, calving to first service, number of services, first service to conception, and days open. Also, lower milk BHBA was associated with a longer herd life, better conformation, and better feet and legs. A higher genetic merit for milk yield was associated with higher milk BHBA, and, therefore, a greater susceptibility to hyperketonemia. Milk BHBA at the first test-day was moderately genetically correlated with fat-to-protein ratio (0.49), body condition score (-0.35), and clinical ketosis (0.48), whereas the genetic correlation with displaced abomasum was near zero (0.07). Milk BHBA can be routinely analyzed in milk samples at test days, and, therefore, provides a practical tool for breeding cows less susceptible to hyperketonemia.

Isolated word recognition of silent speech using magnetic implants and sensors.

There are a number of situations where individuals wish to communicate verbally but are unable to use conventional means-so called 'silent speech'. These include speakers in noisy and covert situations as well as patients who have lost their voice as a result of a laryngectomy or similar procedure. This paper focuses on those who are unable to speak following a laryngectomy and assesses the possibility of speech recognition based on a magnetic implant/sensors system. Permanent magnets are placed on the tongue and lips and the changes in magnetic field resulting from movement during speech are monitored using a set of magnetic sensors. The sensor signals are compared to sets of pre-recorded templates using the dynamic time warping (DTW) method, and the best match is identified. Experimental trials are reported for subjects with intact larynx, typically using 500-1000 utterances used for speaker dependant training and testing. It is shown that recognition rates of over 90% are achievable for vocabularies of at least 57 isolated words: sufficient to drive command-and-control applications.

Multiple pseudo-abscesses following aortic valve replacement.

Prosthetic aortic valve endocarditis is associated with valve ring abscess, conduction abnormalities and a grave prognosis. Aortic root abscess is a serious complication of infective endocarditis with high mortality. We report a case of a patient who had echocardiographic features resembling aortic root abscess along with severe aortic regurgitation, 6 weeks following aortic valve replacement. Valvular dehiscence led to perivalvular abscess like appearance. Infective endocarditis was exluded. He underwent a successful redo aortic valve surgery with slow recovery.

A rare case of multiple right heart myxomas.

Primary tumours of the heart are rare. Myxomas are the most common primary cardiac tumours with an estimated incidence of 0.5 per million population per year. Myxomas are most commonly found in left atrium and are solitary in more than 90% cases. Familial myxomas are rarer and tend to be multiple. We report a rare case of multiple myxomas in the right heart which occurred sporadically, presenting with an episode of pre-syncope.

Genetic analysis of milk urea nitrogen and lactose and their relationships with other production traits in Canadian Holstein cattle.

The objective of this research was to estimate heritabilities of milk urea nitrogen (MUN) and lactose in the first 3 parities and their genetic relationships with milk, fat, protein, and SCS in Canadian Holsteins. Data were a random sample of complete herds (60,645 test day records of 5,022 cows from 91 herds) extracted from the edited data set, which included 892,039 test-day records of 144,622 Holstein cows from 4,570 herds. A test-day animal model with multiple-trait random regression and the Gibbs sampling method were used for parameter estimation. Regression curves were modeled using Legendre polynomials of order 4. A total of 6 separate 4-trait analyses, which included MUN, lactose, or both (yield or percentage) with different combinations of production traits (milk, fat and protein yield, fat and protein percentages, and somatic cell score) were performed. Average daily heritabilities were moderately high for MUN (from 0.384 to 0.414), lactose kilograms (from 0.466 to 0.539), and lactose percentage (from 0.478 to 0.508). Lactose yield was highly correlated with milk yield (0.979). Lactose percentage and MUN were not genetically correlated with milk yield. However, lactose percentage was significantly correlated with somatic cell score (-0.202). The MUN was correlated with fat (0.425) and protein percentages (0.20). Genetic correlations among parities were high for MUN, lactose percentage, and yield. Estimated breeding values (EBV) of bulls for MUN were correlated with fat percentage EBV (0.287) and EBV of lactose percentage were correlated with lactation persistency EBV (0.329). Correlations between lactose percentage and MUN with fertility traits were close to zero, thus diminishing the potential of using those traits as possible indicators of fertility.

Analysis of milk urea nitrogen and lactose and their effect on longevity in Canadian dairy cattle.

The aim of this study was to assess the phenotypic level of lactose and milk urea nitrogen concentration (MUN) and the association of these traits with functional survival of Canadian dairy cattle using a Weibull proportional hazards model. A total of 1,568,952 test-day records from 283,958 multiparous Holstein cows from 4,758 herds, and 79,036 test-day records from 26,784 multiparous Ayrshire cows from 384 herds, calving from 2001 to 2004, were used for the phenotypic analysis. The overall average lactose percentage and MUN for Ayrshires were 4.49% and 12.20 mg/dL, respectively. The corresponding figures for Holsteins were 4.58% and 11.11 mg/dL. Concentration of MUN increased with parity number, whereas lactose percentage decreased in later parities. Data for survival analysis consisted of 39,536 first-lactation cows from 1,619 herds from 2,755 sires for Holsteins and 2,093 cows in 228 herds from 157 sires for Ayrshires. Test-day lactose percentage and MUN were averaged within first lactation. Average lactose percentage and MUN were grouped into 5 classes (low, medium-low, medium, medium-high, and high) based on mean and standard deviation values. The statistical model included the effects of stage of lactation, season of production, the annual change in herd size, type of milk-recording supervision, age at first calving, effects of milk, fat, and protein yields calculated as within herd-year-parity deviations, herd-year-season of calving, lactose percentage and MUN classes, and sire. The relative culling rate was calculated for animals in each class after accounting for the remaining effects included in the model. Results showed that there was a statistically significant association between lactose percentage and MUN in first lactation with functional survival in both breeds. Ayrshire cows with high and low concentration of MUN tended to be culled at a higher than average rate. Instead, Holstein cows had a linear association, with decreasing relative risk of culling with increasing levels of MUN concentration. The relationship between lactose percentage and survival was similar across breeds, with higher risk of culling at low level of lactose, and lower risk of culling at high level of lactose percentage.

Multivariate prediction of major adverse cardiac events after 9914 percutaneous coronary interventions in the north west of England.

OBJECTIVE: To develop a multivariate prediction model for major adverse cardiac events (MACE) after percutaneous coronary interventions (PCIs) by using the North West Quality Improvement Programme in Cardiac Interventions (NWQIP) PCI Registry. SETTING: All NHS centres undertaking adult PCIs in north west England. METHODS: Retrospective analysis of prospectively collected data on 9914 consecutive patients undergoing adult PCI between 1 August 2001 and 31 December 2003. A multivariate logistic regression analysis was undertaken, with the forward stepwise technique, to identify independent risk factors for MACE. The area under the receiver operating characteristic (ROC) curve and the Hosmer-Lemeshow goodness of fit statistic were calculated to assess the performance and calibration of the model, respectively. The statistical model was internally validated by using the technique of bootstrap resampling. MAIN OUTCOME MEASURES: MACE, which were in-hospital mortality, Q wave myocardial infarction, emergency coronary artery bypass graft surgery, and cerebrovascular accidents. RESULTS: Independent variables identified with an increased risk of developing MACE were advanced age, female sex, cerebrovascular disease, cardiogenic shock, priority, and treatment of the left main stem or graft lesions during PCI. The ROC curve for the predicted probability of MACE was 0.76, indicating a good discrimination power. The prediction equation was well calibrated, predicting well at all levels of risk. Bootstrapping showed that estimates were stable. CONCLUSIONS: A contemporaneous multivariate prediction model for MACE after PCI was developed. The NWQIP tool allows calculation of the risk of MACE permitting meaningful risk adjusted comparisons of performance between hospitals and operators.

Coronary artery bypass graft imaging using ECG-gated multislice computed tomography: comparison with catheter angiography.

AIM: To compare the value of multislice computerized tomography (MSCT) in imaging coronary artery bypass grafts (CABGs) by direct quantitative comparison with standard invasive angiography. METHODS: Using MSCT, 50 consecutive patients who had previously undergone CABG surgery and had recently undergone invasive angiography for recurrent angina pectoris, were studied further using MSCT after intravenous injection of non-ionic contrast agent; cardiac imaging was performed during a single breath-hold. Graft anatomy was quantified, using both quantitative coronary angiography (QCA) and MSCT, by different investigators blinded to each other. Reproducibility was quantified using the standard error of the measurement expressed as a percentage in log-transformed values (CV%) and intraclass correlation (ICC). RESULTS: All 150 grafts were imaged using MSCT; only 4 patent grafts were not imaged using selective angiography. Good agreement was achieved between MSCT and QCA on assessment of proximal anastomoses (CV% 25.2, ICC 0.84), mid-vessel luminal diameter (CV% 15.5, ICC 0.91) and aneurysmal dilations (CV% 14.3). Reasonable agreement was reached on assessment of distal anastomoses (CV% 26.7, ICC 0.66) and categorization of distal run-off (ICC 0.73). Good agreement was observed for stenoses of over 50% luminal loss (CV% 8.7, ICC 0.97) but agreement on assessment of less severe lesions was poor (CV% 208.7, ICC 0.51). CONCLUSION: This study demonstrates that CABGs can be quantitatively evaluated using MSCT, and that significant lesions present in all CABG segments can be reliably identified. Agreement between MSCT and QCA for lesions of less than 50% luminal loss was poor.

Health related quality of life of patients with refractory angina before and one year after enrolment onto a refractory angina program.

OBJECTIVE: This study was designed to assess the impact of a refractory angina programme on the health related quality of life for patients with chronic refractory angina (CRA) one year following enrolment. DESIGN: A one year prospective audit. SETTING: Specialist refractory angina clinic at a tertiary cardiac referral centre. PATIENTS: 69 consecutive refractory angina patients referred to a regional refractory angina centre from 1/03/2001 to 1/09/2002. INTERVENTIONS: Pain treatment algorithm in accordance with the recommendations of the national refractory angina guideline committee. MAIN OUTCOME MEASURES: Improvements in quality of life indices were assessed using Seattle angina questionnaire (SAQ), and short form-12 (SF-12) with changes in mood determined using the hospital anxiety and depression (HAD) questionnaire. RESULTS: All dimensions of the SF-12 and SAQ were superior at one year with significant improvement seen with the mental component of SF-12 (p = 0.023), and four of the five SAQ domains, angina stability (p = 0.028), angina frequency (p=0.02), treatment satisfaction (p=0.001) and quality of life (p < 0.001). All the significant changes within the SAQ domains were large enough to be considered clinically relevant. At one year the anxiety and depression domains were significantly improved from baseline (p = 0.015, 0.018) with clinical anxiety levels falling significantly from 55% to 40%, a relative reduction of 28% (p = 0.008). CONCLUSIONS: Implementation of the national refractory angina guidelines in a prospective study of 69 consecutive CRA patients significantly improved health related quality of life status at one year.

The role of bone morphogenetic proteins in ovarian function.

Bone morphogenetic proteins (BMPs) represent the largest subclass of growth factors in the transforming growth factor beta (TGF-beta) superfamily. BMPs have proven to be multifunctional regulators of a wide variety of biological processes in numerous types of cell and tissue. The role of inhibins, activins and TGF-betas (which also belong to the TGF-beta superfamily) in reproduction has been studied extensively over the last 15 years. However, there were no reports on the role of BMPs in the mammalian ovary until 1999 when we reported an intrinsic ovarian BMP system replete with BMP ligands, receptors and novel biological functions. Since this report it has become clear that the BMP system plays an important role in the regulation of ovarian function, evidenced by the ability of BMPs to control granulosa cell proliferation and cytodifferentiation, as well as oocyte development. The physiological relevance of the BMP system has recently been highlighted by the discovery that genetic mutations in the BMP-15 ligand or the BMP type IB receptor lead to critical aberrations in folliculogenesis and ovulation. This review provides a current overview of the rapidly emerging field of the BMP system in mammalian ovarian function.

Follistatin inhibits the function of the oocyte-derived factor BMP-15.

Recent studies have highlighted the importance of a novel oocyte-derived growth factor, bone morphogenetic protein-15 (BMP-15) in the regulation of proliferation and differentiation of granulosa cells in the ovary. Namely, BMP-15 stimulates granulosa cell mitosis and inhibits follicle-stimulating hormone (FSH) receptor mRNA expression in granulosa cell, thereby playing a critical role in the elaborate mechanism controlling ovarian folliculogenesis. At present, however, nothing is known about molecules which may regulate the biological activity of BMP-15. Here we demonstrate evidence that follistatin can form an inactive complex with BMP-15, through which follistatin inhibits BMP-15 bioactivities. The binding of follistatin to BMP-15 was directly demonstrated by a surface plasmon resonance biosensor, and the ability of follistatin to inhibit BMP-15 functions was determined by established BMP-15 bioassays using primary rat granulosa cells. Specifically, follistatin attenuated BMP-15 stimulation of granulosa cell proliferation and reversed BMP-15 inhibition of FSH receptor mRNA expression leading to the suppression of FSH-induced progesterone synthesis. This is the first demonstration of the biochemical interaction and biological antagonism of follistatin and BMP-15, which may be involved in the complex yet well-controlled mechanism of the regulation of follicle growth and development.

Role of ERK1/2 in the differential synthesis of progesterone and estradiol by granulosa cells.

A major concept in mammalian ovarian physiology is that follicle-stimulating hormone (FSH) activates the granulosa cells (GCs) in the Graafian follicle to selectively produce estradiol, but not progesterone, during the follicular phase of the menstrual or estrous cycle. However, given the fact that FSH can induce production of both estradiol and progesterone by GCs cultured in vitro, it has been postulated for a long time that there is a factor present in the ovary that selectively prevents FSH-induced progesterone production. Here, we provide evidence that two members of the mitogen-activated protein kinase family, extracellular signal-regulated kinase-1 and -2 (ERK1/2) can differentially regulate FSH-stimulated estradiol and progesterone production. Using primary rat GCs from early antral follicles cultured in serum-free medium for 48 h, we found that the addition of a specific inhibitor of ERK1/2 activation, U0126, caused the attenuation or enhancement of FSH-induced progesterone or estradiol production, respectively, in a dose-dependent manner. Throughout the 48-h culture period in this culture system ERK1/2 molecules in their activated state (phospho-ERK1/2) were clearly detectable in GCs exposed to FSH. The addition of U0126 caused a decrease in the levels of phosphorylated but not unphosphorylated ERK1/2 which was maintained throughout the 48-h culture, suggesting that U0126 was continuously active to inhibit the phosphorylation of ERK1/2. The divergent regulation of FSH-induced progesterone and estradiol synthesis by U0126 was further supported by demonstrating that U0126 inhibits and stimulates FSH-induced mRNA levels of steroidogenic acute regulatory protein and P450 aromatase, respectively. Collectively, this study clearly identified ERK1/2 as the first intracellular signaling molecules that differentially regulate FSH-induced progesterone and estradiol synthesis in GCs.

Effect of bone morphogenetic protein-7 on folliculogenesis and ovulation in the rat.

We have previously established the presence of a functional bone morphogenetic protein (BMP) system in the ovary by demonstrating the expression of BMP ligands and receptors as well as novel cellular functions. Specifically, BMP-4 and BMP-7 are expressed in theca cells, and their receptors by granulosa cells. These BMPs enhanced and attenuated the stimulatory action of FSH on estradiol and progesterone production, respectively. To investigate the underlying mechanism of the differential regulation, we analyzed mRNA levels for key regulators in the steroid biosynthetic pathways by RNase protection assay. BMP-7 enhanced P450 aromatase (P450(arom)) but suppressed steroidogenic acute regulatory protein (StAR) mRNAs induced by FSH, whereas mRNAs encoding further-downstream steroidogenic enzymes, including P450 side-chain cleavage enzyme and 3beta-hydroxysteroid dehydrogenase, were not significantly altered. These findings suggest that BMP-7 stimulation and inhibition of P450(arom) and StAR mRNA expression, respectively, may play a role in the mechanisms underlying the differential regulation of estradiol and progesterone production. To establish the physiological relevance of BMP functions, we investigated the in vivo effects of injections of recombinant BMP-7 into the ovarian bursa of rats. Ovaries treated with BMP-7 had decreased numbers of primordial follicles, yet had increased numbers of primary, preantral, and antral follicles, suggesting that BMP-7 may act to facilitate the transition of follicles from the primordial stage to the pool of primary, preantral, and antral follicles. In this regard, we have also found that BMP-7 caused an increase in DNA synthesis and proliferation of granulosa cells from small antral follicles in vitro. In contrast to the stimulatory activity, BMP-7 exhibited pronounced inhibitory effects on ovulation rate and serum progesterone levels. These findings establish important new biological activities of BMP-7 in the context of ovarian physiology, including folliculogenesis and ovulation.

Biological function and cellular mechanism of bone morphogenetic protein-6 in the ovary.

The process of ovarian folliculogenesis is composed of proliferation and differentiation of the constitutive cells in developing follicles. Growth factors emitted by oocytes integrate and promote this process. Growth differentiation factor-9 (GDF-9), bone morphogenetic protein (BMP)-15, and BMP-6 are oocyte-derived members of the transforming growth factor-beta superfamily. In contrast to the recent studies on GDF-9 and BMP-15, nothing is known about the biological function of BMP-6 in the ovary. Here we show that, unlike BMP-15 and GDF-9, BMP-6 lacks mitogenic activity on rat granulosa cells (GCs) and produces a marked decrease in follicle-stimulating hormone (FSH)-induced progesterone (P(4)) but not estradiol (E(2)) production, demonstrating not only the first identification of GCs as BMP-6 targets in the ovary but also its selective modulation of FSH action in steroidogenesis. This BMP-6 activity resembles BMP-15 but differs from GDF-9 activities. BMP-6 also exhibited similar action to BMP-15 by attenuating the steady state mRNA levels of FSH-induced steroidogenic acute regulatory protein (StAR) and P450 side-chain cleavage enzyme (P450scc), without affecting P450 aromatase mRNA level, supporting its differential function on FSH-regulated P(4) and E(2) production. However, unlike BMP-15, BMP-6 inhibited forskolin- but not 8-bromo-cAMP-induced P(4) production and StAR and P450scc mRNA expression. BMP-6 also decreased FSH- and forskolin-stimulated cAMP production, suggesting that the underlying mechanism by which BMP-6 inhibits FSH action most likely involves the down-regulation of adenylate cyclase activity. This is clearly distinct from the mechanism of BMP-15 action, which causes the suppression of basal FSH receptor (FSH-R) expression, without affecting adenylate cyclase activity. As assumed, BMP-6 did not alter basal FSH-R mRNA levels, whereas it inhibited FSH- and forskolin- but not 8-bromo-cAMP-induced FSH-R mRNA accumulation. These studies provide the first insight into the biological function of BMP-6 in the ovary and demonstrate its unique mechanism of regulating FSH action.

Gonadotropin-releasing hormone content in the brain and pituitary of male and female grass rockfish (Sebastes rastrelliger) in relation to seasonal changes in reproductive status.

The involvement of individual molecular forms of GnRH in the regulation of reproductive cyclicity in a viviparous marine teleost, the grass rockfish (Sebastes rastrelliger), was evaluated by relating the brain and pituitary content of the neuropeptide to reproductive status. The presence of sea bream (sb) GnRH, chicken GnRH-II, and salmon GnRH in the brain was confirmed by their elution pattern on HPLC and RIA. In addition, HPLC elution profiles suggest that there may be a fourth form of GnRH. All forms of GnRH were found in male and female brains in all reproductive conditions. However, only sbGnRH could be detected in appreciable amounts in the pituitary. Of the four forms of GnRH found in the rockfish, only sbGnRH fluctuated during the reproductive cycle and large accumulations were detected in the brains and pituitaries of postspawn females and regressed males. The accumulation of sbGnRH at the end of the reproductive cycle is suggested to reflect a decline in GnRH secretion relative to synthesis. The dominance of sbGnRH in the pituitary and its individual fluctuation in relation to seasonal changes in reproductive status suggests that sbGnRH is an important regulator of gonadotropin-mediated reproductive activity in rockfish.