Domestic animal endocrinology最新文献

Incretin hormones potentiate the glucose-induced insulin secretion following enteral nutrient intake. The best characterised incretin hormones are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) which are produced in and secreted from the gut in response to nutrient ingestion. The property of incretins to enhance endogenous insulin secretion only at elevated blood glucose levels makes them interesting therapeutics for type 2 diabetes mellitus with a better safety profile than exogenous insulin. While incretin therapeutics (especially GLP-1 agonists, and more recently also GLP-1 / GIP dual agonists and other drugs that influence the incretin metabolism (e.g., dipeptidyl peptidase-4 (DPP-4) inhibitors)) are already widely used treatment options for human type 2 diabetes, these drugs are not yet approved for the therapy of feline diabetes mellitus. This review provides an introduction to incretins and feline diabetes mellitus in general and summarises the current study situation on incretins as therapeutics for feline diabetes mellitus to assess their possible future potential in feline medicine. Studies to date on the use of GLP-1 receptor agonists (GLP-1RA) in healthy cats largely confirm their insulinotropic effect known from other species. In diabetic cats, GLP-1RAs appear to significantly reduce glycaemic variability (GV, an indicator for the quality of glycaemic control), which is important for the management of the disease and prevention of long-term complications. However, for widespread use in feline diabetes mellitus, further studies are required that include larger numbers of diabetic cats, and that consider and test a possible need for dose adjustments to overweight and diabetic cats. Also evaluation of the outcome of GLP-1RA monotherapy will be neceessary.

The aim of this study was to determine the effect of body condition score (BCS) on metabolic and endocrine parameters in pregnant Criollo mares (n=41), which were categorized according to their BCS as obese (7 to 9 BCS, n=26) or normal (5 to 7, n=15). Blood samples were taken during gestation in 3 periods: between 3.5 and 5 months (I), 8 and 9 months (II) and in the last month of gestation (III). The data was analyzed in the statistical model by mixed procedures, including BCS, gestational period and their interaction as fixed effects. BCS was only different in period I, as normal mares increased their BCS in the later periods. Leptin concentrations were greater in obese mares when compared to non-obese mares during all sampling periods (P<0.01), while glucose concentrations were also greater in the former group (P<0.01) but only during the first sampling period. Insulin concentrations and homeostatic model assessment for insulin resistance (HOMA-IR) index were greater also in obese mares in periods I and III (P<0.05). Adiponectin concentrations in period I were lower in obese mares (P<0.05). Cholesterol concentrations increased during gestation, and obese mares tended to have greater concentrations than nonobese mares (P<0.1). Triglyceride concentrations were not affected by group or gestational period. This study revealed adaptations in carbohydrate and lipid metabolism during gestation in mares. Several parameters are dependent on the degree of body fat reserves, which are reflected in the concentrations of biomarkers such as leptin and adiponectin. Insulin concentration in obese mares was higher than non-obese mares at the end of gestation, a similar profile was observed for HOMA-IR although cutoff values are yet still to be validated.

GATA4 plays a pivotal role in the reproductive processes of mammals. However, the research on GATA4 in goat ovary is limited. This study aimed to study the expression and function of GATA4 in goat ovary. Utilizing real-time PCR and western blot analysis, we studied the expression and regulatory mechanisms of GATA4 in goat ovary and granulosa cells (GCs). We found that GATA4 was expressed in all follicle types in the goat ovary, with significantly higher levels in GCs of larger follicles (>3 mm) compared to those in smaller follicles (<3 mm). Additionally, we demonstrated that human chorionic gonadotrophin (hCG) induced GATA4 mRNA expression via the activation of PKA, MEK, p38 MAPK, PKC, and PI3K pathways in vitro. Our study also showed that hCG suppressed the levels of miR-200b and miR-429, which in turn directly target GATA4, thereby modulating the basal and hCG-induced expression of GATA4. Functionally, we examined the effect of siRNA-mediated GATA4 knockdown on cell proliferation and hormone secretion in goat GCs. Our results revealed that knockdown of GATA4, miR-200b, and miR-429 suppressed cell proliferation. Moreover, knockdown of GATA4 decreased estradiol and progesterone production by inhibiting the promoter activities of CYP11A1, CYP19A1, HSD3B, and StAR. Collectively, our findings suggest a critical involvement of GATA4 in regulating goat GC survival and steroidogenesis.

Feline hypersomatotropism (HST) is typically associated with diabetes mellitus (DM), whereas HST without concurrent DM has only been reported in a few cases. Weight gain may be observed in cats with HST. The aims of this study were to evaluate circulating insulin-like growth factor-1 (IGF-1) in non-diabetic cats with overweight/obesity, to screen this population for the presence of HST, and to assess whether there is a correlation between body weight/body condition score (BCS) and serum IGF-1 concentration in overweight/obese cats. In this prospective study, 80 overweight/obese cats from referral centers in Buenos Aires (Argentina) were evaluated. Serum IGF-1 was measured as part of the routine tests for overweight/obesity. Non-diabetic cats were included in the study if they had a BCS>6/9. Twenty-nine cats were classified as overweight (BCS 7/9), whereas 51 were classified as obese (BCS 8-9/9). Median serum IGF-1 concentrations of cats with BCS 7/9, 8/9, and 9/9 were 570 ng/ml (range 123-1456 ng/ml), 634 ng/ml (range 151-1500 ng/ml), and 598 ng/ml (range 284-2450 ng/ml), respectively. There was a positive linear correlation between serum IGF-1 concentrations and body weight (r= 0.24, 95% CI 0.01-0.44 P=0.03), and between IGF-1 and BCS (r= 0.27, 95% CI 0.08-0.44 P=0.004). In total, 8.75% (95% confidence interval 3.6-17.2%) of the cats with overweight/obesity had IGF-1 concentrations >1000 ng/ml. Pituitary enlargement was detected on computed tomography in 4/7 cases. These seven cats showed varying degrees of phenotypic changes consistent with acromegaly. A proportion of 8.75 % of overweight/obese non-diabetic cats from referral centers in Buenos Aires had serum IGF-1 concentration in a range consistent with HST in diabetic cats. Likewise, 5% of overweight/obese cats were likely to be diagnosed with HST, supported by evidence of pituitary enlargement. Serum IGF-1 concentrations were positively correlated with body weight and BCS in this population of cats. This study highlights the relevance of screening different populations of non-diabetic cats to increase the detection of HST/acromegaly.

Freemartinism is the most common congenital anomaly among sexual disorders in dairy cows. This syndrome typically occurs in different-sex twin pregnancies and causes vascular anastomoses to form with the placenta in the early stages of fetal development. The study aims to determine the effectiveness of Anti-müllerian hormone (AMH) levels in calves and heifers of different age groups for diagnostic factors and to investigate the potential consequences of different hormone levels in different age groups on some liver biochemical parameters. The study involved 50 cattle from diverse age categories, divided into the freemartin group (FM Group, n=25) and the control group (C Group, n=25). Both FM and control groups were further divided into early-age (3-5 months), middle-aged (5-9 months), and older-aged groups (9-12 months). Serum AMH levels, along with total protein, albumin, and total cholesterol levels, were measured. While no statistically significant difference in AMH levels was observed in the early-age group (P:0.53), significant differences were determined in the middle (P:0.015) and older-age groups (P:0.01), where the FM group exhibited significantly decreased AMH levels compared to the control group. The evaluation of liver biochemistry revealed a statistically significant difference in total protein levels between the FM and control groups in the older age group (P:0.033). Consequently, it is reasonable to suggest that AMH levels may serve as a valid parameter for diagnosing freemartin syndrome in calves aged older than five months. Conversely, particularly in young calves, no significant differences in liver functionality were observed between freemartin-affected and healthy calves.

The aim of the present study was to examine the influence of monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) on ovarian cell functions. Rabbit ovarian granulosa cells were cultured with or without MCP-1 or PAI-1 (at 0, 0.1, 1, or 10 ng/ml). Cell viability, proliferation, cytoplasmic apoptosis and release of progesterone and estradiol were measured by Cell Counting Kit-8 (CCK-8), BrdU incorporation, and cell death detection assays and ELISA. The addition of either MCP-1 or PAI-1 increased cell viability and proliferation and decreased apoptosis. MCP-1 promoted, while PAI-1 suppressed, progesterone release. Both MCP-1 and PAI-1 reduced estradiol output. The present results suggest that MCP-1 or PAI-1 can be physiological promoters of rabbit ovarian cell viability and proliferation, inhibitors of apoptosis and regulators of ovarian steroidogenesis.

This study evaluated the efficiency of prostaglandin F2α (PGF) to hasten ovulation in weaned sows. In experiment I, weaned sows detected in estrus (0 h) received: no hormone (Control; n = 56); 0.5 mg PGF IM at 0 h and 2 h (PGF0; n = 56); or 0.5 mg PGF IM at 24 h and 26 h (PGF24; n = 55). In experiment II, weaned sows that did not express estrus signs until 72 h after weaning (0 h) were assigned to: no hormone (Control; n = 45); 10 µg buserelin acetate IM at 0 h (Buserelin; n = 43); 0.5 mg PGF IM at 34 h and 36 h (PGF; n = 44); or 10 µg buserelin acetate IM at 0 h plus 0.5 mg PGF IM at 34 h and 36 h (Buserelin + PGF; n = 45). In experiment I, no effect of PGF on the interval treatment onset to ovulation was observed (P > 0.05), and no treatment effect was observed on the relative or cumulative proportion of females that ovulated post-treatment onset (P > 0.05). In experiment II, treatment onset to ovulation interval was shorter for Buserelin group than for PGF group (P < 0.05), and a higher cumulative percentage of Buserelin treated sows ovulated up to 48 h compared to PGF and Control groups (P < 0.01), with no differences from Buserelin + PGF. Treatments did not affect total number of piglets born in both experiments (P > 0.05). In conclusion, PGF did not hasten ovulation timing or affect litter size in weaned sows.

The aim of this study was to produce a longer proestrus by early administration of prostaglandin F2α (PGF) in a timed artificial insemination (TAI) protocol in non-suckling Bos taurus (Angus crossbreed) beef cows. On day 0, cows (n = 489) were treated with an intravaginal 1 g progesterone (P4) device and 2 mg of estradiol benzoate. On day 7, cows were randomized into two groups: PGF7(n = 244; 500 µg of sodium cloprostenol 24 h before P4 device removal) or PFG8 (n = 245; 500 µg of sodium cloprostenol at P4 device removal). On day 8, P4 device was removed and cows received 0.5 mg of estradiol cypionate. All cows were submitted to TAI on day 10 (48–50 hours after P4 device removal). Cows treated with PGF on day 7 had greater expression of estrus (91.3 vs 79.1 %; P = 0.0011), regardless of CL presence at beginning of the protocol. Cows from PGF7 group had lower circulating P4 concentrations on day 8 in comparison with PGF8 treated cows (1.86 vs 2.99 ng/mL; P < 0.001). However, preovulatory follicle diameter did not differ among treatments at TAI (11.9 vs 11.8 mm; P = 0.7881). Pregnancy per TAI (P/TAI) was greater for PGF7 (63.9 vs 50.6 %; P = 0.0114) than PGF8 treated cows. In cows with follicles <8.5 mm at TAI, expression of estrus (33.3 vs 26.6 %; P = 0.6427) and P/TAI (40 vs 26.6 %; P = 0.3657) were low in both PGF7 and PGF8 treated cows, respectively. In cows with medium follicle size (8.5 to 11.9 mm) PGF7 treated cows had greater expression of estrus (90.5 vs 80 %; P = 0.033) and P/TAI (62.2 vs 49 %; P = 0.053). In cows with follicles >12 mm, expression of estrus was greater for PGF7 than PGF8 treated cows (99.1 vs 93.3 %; P = 0.045), however P/TAI did not differ (68.2 vs 59 %; P = 0.149). In cows with P4 < 1.99 ng/mL on day 8, expression of estrus was similar between PGF7 and PGF8 treated cows (92.6 vs 90.4 %; P = 0.53), and P/TAI tended to be greater for PGF7 than PGF8 treated cows (63 vs 52.1 % P = 0.076). However, in cows with P4 > 2 ng/mL PGF7 cows had higher expression of estrus (89 vs 67.5 %; P = 0.0005) and P/TAI (64.8 vs 48.7 %; P = 0.021) than PGF8. Thus, increasing the proestrous period by inducing luteolysis 24 hours earlier than removing the P4 intravaginal device enhanced fertility in non-suckling cyclic beef cows by increasing expression of estrus and P/TAI.

Mares resume ovarian activity rapidly after foaling. Besides follicle-stimulating hormone (FSH) and luteinizing hormone (LH), the pituitary synthesizes prolactin and growth hormone which stimulate insulin-like growth factor (IGF) synthesis in the liver. We tested the hypothesis that follicular growth is initiated already antepartum, mares with early and delayed ovulation differ in IGF-1 release and that there is an additional IGF-1 synthesis in the placenta. Plasma concentrations of LH, FSH, IGF-1, IGF-2, activin and prolactin. IGF-1, IGF-2, prolactin and their receptors in placental tissues were analyzed at the mRNA and protein level. Follicular growth was determined from 15 days before to 15 days after foaling in 14 pregnancies. Mares ovulating within 15 days postpartum formed group OV (n=5) and mares not ovulating within 15 days group NOV (n=9). Before foaling, follicles with a diameter >1 cm were present in all mares and their number increased over time (p<0.05). Follicle growth after foaling was more pronounced in OV mares (day p<0.001, group p<0.05, day x group p<0.05) in parallel to an increase in LH concentration (p<0.001, day x group p<0.001) while FSH increased (p<0.001) similarly in both groups. Plasma concentrations of IGF-1 and prolactin peaked one day after foaling (p<0.001). The IGF-1 mRNA abundance was higher in the allantochorion but lower in the amnion of OV versus NOV mares (group p=0.01, localization x group p<0.01). The IGF-1 receptor mRNA was most abundant in the allantochorion (p<0.001) and IGF-1 protein was expressed in placental tissue without differences between groups. In conclusion, follicular growth in mares is initiated before foaling and placental IGF-1 may enhance resumption of ovulatory cycles.

Colostrum and milk offer a complete diet and vital immune protection for newborn mammals with developing immune systems. High immunoglobulin levels in colostrum serve as the primary antibody source for newborn piglets and calves. Subsequent milk feeding support continued local antibody protection against enteric pathogens, as well as maturation of the developing immune system and provide nutrients for newborn growth. Mammals have evolved hormonal strategies that modulate the levels of immunoglobulins in colostrum and milk to facilitate effective lactational immunity. In addition, hormones regulate the gut-mammary gland-secretory immunoglobulin A (sIgA) axis in pregnant mammals, controlling the levels of sIgA in milk, which serves as the primary source of IgA for piglets and helps them resist pathogens such as PEDV and TGEV. In the present study, we review the existing studies on the interactions between hormones and the gut-mammary-sIgA axis/lactogenic immunity in mammals and explore the potential mechanisms of hormonal regulation that have not been studied in detail, to draw attention to the role of hormones in influencing the immune response of pregnant and lactating mammals and their offspring, and highlight the effect of hormones in regulating sIgA-mediated anti-infection processes in colostrum and milk. Discussion of the relationship between hormones and lactogenic immunity may lead to a better way of improving lactogenic immunity by determining a better injection time and developing new vaccines.