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PubMed2006

The postpartum buffalo: I. Endocrinological changes and uterine involution.

To maintain a calving interval of 13-14 months in buffaloes, successful breeding must take place within 85-115 days after calving. Disturbances during this period due to delay of uterine involution or resumption of estrous activity are likely to prolong the calving interval and reduce the lifetime reproductive and productive efficiency. In this article literature on endocrinological changes in the peripartum period and on factors affecting uterine involution are reviewed. The available information indicated that although the availability of releasable FSH does not appear to be a limiting factor for resumption of postpartum cyclicity a substantial increase of releasable LH and replenishment of pituitary stores occurred around Day 20 in dairy and Day 30 in swamp buffaloes. There is evidence that follicular activity is resumed early (15-30 days) in the postpartum period. However, the factors which initiate release of appropriate LH pulses, follicular maturation and ovulation in the postpartum buffalo need further studies. The mean interval to complete uterine involution varied widely between 19 and 52 days. Assessment of cervical and uterine horn diameters by rectal palpation alone is not satisfactory to diagnose delayed uterine involution and possible subclinical uterine infection. Vaginal inspection can be included as a fundamental part of postpartum genital examination for diagnosis of such case. Uterine involution, however, does not seem to be a limiting factor for achievement of satisfactory fertility in the postpartum buffalo but the main determinant is resumption of estrous activity.

Animals↗
PubMed2006

Advances in endocrinology of aging research, 2005-2006.

The purpose of this brief review is to highlight some of the more important advances in endocrinology of aging research over the past year. Four advances were chosen and briefly described. First, exploration of the early steps in the generation of the internal steroidal hormonal signal involved in lifespan extension via the insulin/IGF-like signaling pathway in the nematode by two research groups revealed that the product of cholestanoic acid derivatives metabolized by a cytochrome P-450-like protein activates a protein with homology to the mammalian nuclear receptor superfamily, a process strikingly similar to the steroid hormone signaling pathway documented in mammalian systems. Second is the discovery that sirtuins, proteins that regulate lifespan in model organisms, enhance pancreatic insulin secretion in mice following a glucose challenge, suggesting the potential to regulate mammalian lifespan through regulation of the insulin signaling pathway. Third, the newly discovered hormone klotho, which also plays a role in regulating lifespan, in this case in mice, is reported to not only negatively affect insulin sensitivity but, perhaps more importantly, significantly affects calcium and phosphate metabolism as a required cofactor of Fgf-23 signaling. Finally the gonadotropin FSH is shown to directly affect bone density in mice separate from any direct effect of estrogen, suggesting that reproductive hormones other than estrogen can directly impact menopause-associated pathophysiology in non-reproductive tissues.

Aging↗
PubMed2006

Metabolic syndrome and age-related dementia: endocrinological aspects of adaptation to aging.

Metabolic syndrome is one of the determinants of lifespan in Japan. In order to prevent the acute vascular events, intervention is recommended. However, management of patients with this syndrome increased the number of patients with cognition decline and depressive state. Endocrinological studies with human and experimental animals showed that there is a negative relationship between progression of metabolic syndrome and occurrence of mental disorders. In this review, we summarize our clinical and experimental data, and discuss on the mechanism of the metabolic syndrome prevention of progression of age-related mental disorder.

Adaptation, Physiological↗
PubMed2004

An overview of the endocrinology of skeletal muscle.

Endocrine regulation of the balance between skeletal muscle anabolism and catabolism has been investigated extensively. Factors determining whether hormones exert anabolic or catabolic influences are multifaceted and often unclear. Testosterone, growth hormone, insulin and insulin-like growth factor-I have complex anabolic effects, some of which have only recently been elucidated, and are important regulators of muscle remodeling, whereas glucocorticoids have direct catabolic effects and induce muscle protein loss. The effects of estrogen are poorly understood and warrant further study. We review recent literature and evaluate the hormones driving skeletal muscle anabolism and catabolism, which ultimately dictate the endocrinology and metabolism of skeletal muscle in humans. Understanding hormonal regulation of skeletal muscle remodeling might facilitate development of improved hormone-mediated therapies for muscle wasting conditions.

Animals↗
PubMed2005

Endocrinology of pregnancy and early pregnancy detection by reproductive hormones in reindeer (Rangifer tarandus tarandus).

The endocrinology was studied throughout pregnancy in reindeer (Rangifer tarandus tarandus) located in Oulu, Finland (65 degrees N, 25 degrees E) with 13 captive, semi domestic adult females. Blood samples were analyzed for plasma progesterone (P4), estradiol (E2) and estrone sulphate (E1SO4), 15-ketodihydro-PGF2alpha (PG-metabolite) and pregnancy associated glycoproteins (PAG). The mean plasma P4 concentration peaked twice during gestation: at around 24 and three weeks prior to calving. In pregnant females the plasma PAG concentration increased over basal concentrations 21-30 days after the estimated day of conception and peaked at the time of calving. The concentrations of E2 and E1SO4 remained low until 60 days before calving when a rapid increase was found for both hormones. The mean plasma concentration of PG-metabolite increased throughout pregnancy to a maximum at parturition. The estimated mean (range) gestation length was 216 (212-220) days. Judged from measures on reproductive organs collected from 86 free-ranging, semi-domestic female reindeer of unknown age presented for slaughter at Roros, Norway (63 degrees N, 11 degrees E) in the second week of December 1999, it was concluded that the breeding season lasted from early September until the end of November. The results also showed that plasma PAG concentration could provide a tool for detection of pregnancy in reindeer.

Animals↗
PubMed2006

Comparative endocrinology of domestic and nondomestic felids.

The ability to track gonadal and adrenal activity via hormones is key to optimizing health and reproduction. Through decades of study, a great deal has been learned about the biology of female domestic cats, including endocrine function. More recently, comparative endocrine studies have greatly expanded our knowledge base of nondomestic felids as well. The latter has been possible largely through the development of noninvasive fecal steroid metabolite analysis techniques, which currently is the method of choice for monitoring endocrine function in wildlife species, including felids. It now is well-recognized that a range in endocrine patterns exists among Felidae, with many traits and mechanisms being uncommon, if not unique. There is a high degree of variability in the type of ovulation (spontaneous versus induced) expressed across the taxon. Even within species, some individuals exhibit ovulation that is only induced, whereas others ovulate spontaneously as well. Steroid metabolism also differs in that metabolites are excreted almost exclusively in feces, with very little steroid found in urine. Across species there are marked differences in seasonal and social influences on reproduction, adrenal responses to husbandry practices, and ovarian responses to assisted reproductive procedures. This means that developing strategies to improve health and reproduction of felids must be done on a species by species basis. This paper summarizes current knowledge on the reproductive endocrinology of female domestic and nondomestic cats, and describes how the rapidly growing endocrine database is aiding ex situ management efforts.

Animals↗
PubMed2005

Complete sequence of Litopenaeus vannamei (Crustacea: Decapoda) vitellogenin cDNA and its expression in endocrinologically induced sub-adult females.

The gene that encodes vitellogenin (Vg), the precursor of the major yolk protein, vitellin, is expressed during vitellogenesis in decapod crustaceans. In this study, we sequenced the full-length cDNA from the Pacific white shrimp Litopenaeus vannamei Vg gene (LvVg). This is the first open thelycum penaeid shrimp Vg cDNA to be sequenced. The transcript encodes a 2587 amino acid polypeptide with up to 85% identity to Vg of different penaeid species. Peptide mass fingerprints (PMFs) of the vitelline polypeptides suggest that the predicted endoprotease cleavage site at amino acids 725-728 does indeed undergo cleavage. Five prominent high-density lipoprotein polypeptides of masses 179, 113, 78, 61, and 42kDa were isolated from vitellogenic ovary, and their PMFs were determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) spectrometry. It is likely that these polypeptides are all products of the LvVg gene. Removal of the X-organ sinus gland complex (XO-SG), which secretes the neurohormones that control the endocrine system regulating molt and reproduction, can induce both these processes. During the course of a number of molt cycles in induced sub-adult females, periodic ovarian growth and resorption were observed. Ovary growth correlated with LvVg expression in both the hepatopancreas and the ovary. Expression in ovaries of induced intermolt-early premolt females was significantly higher compared to all other sub-groups. Expression in ovaries of induced females was significantly higher compared to hepatopancreas at all molt cycle stages. Periodicity of molt and vitellogenesis in endocrinologically induced sub-adult shrimps may serve as a model to study alternate regulation of gene expression during these two processes.

Amino Acid Sequence↗
PubMed1987

The endocrinologic evaluation of a 45,X true hermaphrodite.

A 13-year-old 45,X girl presented with spontaneous menses and the acute onset of progressive hirsutism. Complete endocrinologic evaluation of hirsutism was unremarkable. An exploratory laparotomy revealed a gonad containing ovarian and testicular tissue. Chromosome analysis from four different tissues confirmed the karyotype to be 45,X. She was H-Y antigen positive.

Adolescent↗
PubMed2003

Relationship among maternal serum endocrinology, placental karyotype, and intervillous circulation in early pregnancy failure.

OBJECTIVE: To evaluate the relationship among maternal serum endocrinology, placental karyotype, and intervillous blood flow in missed miscarriage. DESIGN: Cross-sectional study of maternal serum, transvaginal ultrasound/Doppler, and placental cytogenetic and immunohistochemical investigations. SETTING: Tertiary care academic hospital. PATIENT(S): One hundred fifty-two women with missed miscarriage between 7 and 13 weeks of gestation. INTERVENTION(S): Ultrasound features, placental intervillous circulation findings on color Doppler imaging, and maternal serum level of alpha-fetoprotein (AFP), beta-hCG, E(2), P, and inhibin A were compared retrospectively with placenta karyotype and hCG immunochemistry. MAIN OUTCOME MEASURES: Data were analyzed according to karyotype results, presence or absence of an intervillous circulation, and delay between fetal demise and evacuation. RESULT(S): The presence of intervillous blood flow and serum concentrations of the different hormones were independent of placental karyotype. Serum beta-hCG and P were significantly higher in cases with intervillous blood flow. No difference in immunostaining for beta-hCG was found between placental tissues from normal pregnancies and missed miscarriages, but significantly higher villous beta-hCG content was found on Western blotting in miscarriage with a recent fetal demise. CONCLUSION(S): The excessive entry of maternal blood inside the placenta in the early stage of most miscarriages is unrelated to conceptus karyotype, and hCG features may reflect a temporary attempt of the trophoblast to stabilize after the initial oxidative insult.

Abortion, Spontaneous↗
PubMed1988

Alterations in carbohydrate metabolism as they apply to reproductive endocrinology.

This review has characterized the current state of knowledge of four clinical situations in which an interrelationship of gynecology, endocrinology and carbohydrate metabolism is recognized. The literature contains conflicting descriptions of changes in glucose homeostasis during the menstrual cycle and while using birth control pills. Physiologic changes in receptor number have been demonstrated in each of these situations, so failure to observe differences using glucose tolerance testing may reflect an in vivo homeostatic response to changes in these hormone levels. Thus, in vivo identification of alterations in carbohydrate metabolism induced by endogenous or exogenous steroids may require utilization of models that prevent these homeostatic mechanisms. The association between hyperandrogenism and hyperinsulinism has been better characterized, but the relationship is complicated by the frequent coexistence of obesity. The association may be due to insulin-stimulated ovarian androgen production, and insulin insensitivity may reflect a postreceptor defect. Insulin and its metabolic effects have also been implicated in ovulatory dysfunction in women with diabetes mellitus and identified as a factor affecting all levels of the hypothalamic-pituitary-ovarian axis. A clearer understanding of these relationships and their application to clinical management await further study.

Androgens↗
PubMed1989

Reproductive endocrinologic alterations in female asymptomatic obesity.

Excess body fat has been clearly associated with an increased risk of oligo-ovulation and endometrial/breast carcinoma. The connection has been assumed to lie within derangements of the metabolic/endocrine compartments, particularly of estrogens and androgens. To differentiate the effect of obesity from its related disease process, an attempt has been made to define the reproductive-endocrinologic alterations encountered in otherwise asymptomatic obese women. Androgen metabolism is accelerated in obesity. It is not clear whether the increased clearance precedes or follows the accelerated production of androgens. A servocontrol mechanism appears to be operative in these asymptomatic individuals, maintaining plasma steroid levels normal. The unbound fraction of T may be somewhat increased in overweight women with predominantly upper body fat deposition. The increased clearance of androgen may arise from an obesity-related depression in SHBG concentration (e.g., for T, E2, delta 5-diol, etc.). Adipose tissue, by virtue of the lipid solubility of most of these steroids, concentrates androgens, estrogens, and progesterone. This steroid sequestration not only contributes to the obesity-related increase in androgen clearance but also leads to an extremely enlarged total body steroid pool. Fat tissue sequestration also increases the concentration of androgens in the vicinity of adipose stromal cells, possibly encouraging their aromatization. Adipose tissue also has a moderate degree of 17-hydroxysteroid dehydrogenase activity, which appears to stimulate the conversion of A to T. Finally, alterations in peripheral and hepatic conjugation and an accelerated urinary excretion may contribute to the elevated clearance of androgens. The accelerated PR of androgens may simply result as compensation for the elevated MCR in obesity. Nonetheless, evidence of alteration(s) in adrenocortical steroidogenesis has been presented suggesting a selective obesity-related enhancement in adrenal androgen secretion. These remain to be confirmed. Nonetheless, adrenocortical abnormalities may arise secondary to the influence of other circulating and intra-adrenal factors, including insulin, prolactin, estrogens, and androgens. It is not known whether the accelerated androgen metabolism or the aberrant adrenal steroidogenesis improve with weight reduction. Excess body fat increases androgen aromatization which, together with an obesity-related decrease in SHBG, is associated with mildly elevated levels of E1 and free E2 in postmenopausal women. Although premenopausal obese individuals have the same tendency, the far greater ovarian estrogen secretion overshadows any differences. The bulk of aromatization activity in fat lies in the stromal comportment. The major substrate for peripheral estrogen production is A. Testosterone also contributes to the estrogen pool via its conversion to E2.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed2003

An endocrinological update in toads: disparity between the cardiovascular effects of two angiotensin II analogs.

This study was undertaken to test the hypothesis that, in toads, the pressor effects of angiotensin II (ANG II) are partly due to the secondary effects of catecholamines. In Bufo marinus, blood pressure responses to bullfrog ([Val(5)]) ANG II administration were measured in animals pretreated (experimental group) and not pretreated (control group) with phentolamine, an alpha-adrenergic antagonist. At 1, 2, and 4 min following ANG II administration (50 ngkg(-1)), mean arterial pressure (MAP) of the experimental group was significantly less than in the control group (27.9+/-1.0, 28.2+/-1.6, and 25.8+/-2.1 mmHg versus 45.1+/-1.0, 39.4+/-2.8, and 35.5+/-3.6, respectively; n=6). Heart rate (f(H)) was unaffected by phentolamine. These data support our hypothesis. Previous authors, using human ([Ile(5)]) ANG II, have concluded that alpha-adrenergic mechanisms are not involved in the pressor effects of ANG II in B. marinus. In a separate group of toads, we examined MAP and f(H) responses to similar doses of human and bullfrog ANG II (100 ngkg(-1)). Bullfrog ANG II caused MAP to reach higher peak values (56.5+/-2.6 versus 37.2+/-0.4 mmHg; n=7) in less time (approximately 1 min versus approximately 8 min) than human ANG II. Furthermore, bullfrog ANG II caused f(H) to significantly increase from 41.3+/-5.1 to 79.3+/-2.3 beats min(-1) (at 1 min) whereas human ANG II caused no significant changes in f(H) throughout the measured time course. Higher doses of human ANG II (100 microgkg(-1)) invoked slow but large increases in MAP with non-significant decreases in f(H). These additional data suggest that the choice of exogenously administered hormone is an important one to consider in comparative endocrinological studies.

Adrenergic alpha-Antagonists↗
PubMed1992

Acute hemodynamic and endocrinological effects of partial fetal bladder obstruction.

The pathophysiology of fetal urinary obstruction has not been elucidated. Using a unique, reproducible and easily reversible animal preparation, we studied the acute hemodynamic and endocrinological responses to partial fetal bladder obstruction in 16 ovine fetuses at 115 days of gestation (term 147 days). After partial obstruction blood pressure and renal weight increased significantly for at least 72 hours. Renal blood flow trended upwards, particularly from 24 to 72 hours, although this change was not statistically significant. Plasma renin activity was significantly increased during the first 24 hours after obstruction but it returned to baseline thereafter. Plasma cortisol or catecholamine concentrations remained unchanged. The time course and pattern of hemodynamic changes in this fetal sheep preparation of partial urinary obstruction differ significantly from those reported in other preparations.

Animals↗
PubMed1978

Clinical and endocrinological evaluation of patients with congenital microphallus.

Eight patients with congenital microphallus were investigated. Plasma luteinizing hormone, follicle-stimulating hormone, testosterone and androstenedione levels were obtained in all cases. In addition, the response to the administration of human chorionic gonadotropin, luteinizing horomone-releasing hormone and adrenocorticotropic hormone, the assessment of testicular histology by electron microscopy and the measurement of dihydrotestosterone formation by preputial skin were determined in some patients. The results of these studies were compared to similar studies in 6 normal prepubertal boys, 4 boys with bilateral cryptorchidism, 1 male infant with anorchia and 1 adult with hypogonadotropic hypogonadism. The clinical and endocrinological findings in the 8 patients with microphallus can be divided into 2 distinct categories. In 5 patients the disorder is familial, gonadotropin levels are low and there is a normal response to stimulation with chorionic gonadotropin. The data are compatible with the possibility that 3 (possibly 5) of the 8 patients with microphallus have hypogonadotropic hypogonadism. In the other group the cases are sporadic, serum luteinizing hormone and follicle-stimulating hormone levels are elevated and plasma testosterone failed to increase after short-term treatment with chorionic gonadotropin. In these patients a primary testicular disorder appears to be responsible. Experimental and clinical evidence suggests that microphallus results from defective testicular function during the second and third trimesters of pregnancy, either as the result of defective gonadotropin secretion or defective androgen synthesis.

Adolescent↗
PubMed1978

Microphallus: clinical and endocrinological characteristics.

The clinical and endocrinological features of 15 male subjects with small but normally formed external genitalia are reviewed. Nine of these patients had a simple microphallus alone, while the other 6 patients exhibited associated central nervous system defects. The endocrine data obtained from both groups were the same and were consistent with defective hypothalamic function. Parenteral testosterone seems to be the present treatment of choice but we believe it should be started early in life to take advantage of the greater hyperplastic response of the young.

Adolescent↗
PubMed2002

Reproductive endocrinology and postweaning performance in the multiparous sow. Part 1. Influence of metabolic status during lactation.

The metabolic status of the sow during lactation might influence reproductive endocrinology and the postweaning reproductive performance. With regard to the multiparous sow, previous studies addressing this topic are scarce and the results inconsistent. Blood samples were collected from 18 multiparous sows during lactation and after weaning for analysis of nonesterified fatty acids (NEFA), triglycerides, creatinine, urea progesterone, LH, and estradiol-17beta. Based on the average preweaning NEFA levels the sows were divided into a "high" and a "low" catabolism group. The NEFA values were higher in the "high" group during each of the last 3 weeks of lactation. The levels of urea, creatinine and progesterone were similar (P > 0.05) in the two groups throughout the study. Reproductive functions seemed equally inhibited during lactation in the two groups and there were no differences in postweaning reproductive performance. The results suggest that metabolic rate during lactation varies considerably between equally nourished multiparous sows but this has no influence on postweaning reproductive performance.

Animals↗
PubMed2001

Recent advances in bovine reproductive endocrinology and physiology and their impact on drug delivery system design for the control of the estrous cycle in cattle.

When methods of drug intervention are being developed to control estrous cycles, a thorough understanding of the endocrine and functional changes together with the reproductive behavior of the animals are essential. This review presents our current knowledge on reproductive endocrinology, physiology and behavior, and the methods of drug intervention to control estrous cycles. It also describes current efforts to develop advanced drug delivery systems that meet the animal scientist's demands to control the estrous cycle in cattle.

Animals↗