Luteinizing hormone (LH) response to different doses of synthetic gonadotropin releasing hormone (GnRH) in prepubertal gilts

The object of this investigation was to study luteinizing hormone (LH) response to different doses of synthetic gonadotropin-releasing hormone (GnRH) in prepubertal gilts. Four crossbred prepubertal gilts, 128–134 days old and body weight 57–63 kg, were used in this study. Four doses, 0. 5, 25 and 125 μg, of GnRH were administered via a jugular vein catheter in a latin square design. Each treatment consisted of 3 injections at 90 min intervals. Frequent blood samples were taken during a period of 90 min before up to 90 min after treatment. Total LH responses were measured from post-treatment samples as the area under the curve above base level obtained from pre-treatment samples. A positive relationship between GnRH dose and LH release was obtained in all gilts, except for 1 treatment given to a gilt with high plasma level of oestradiol-17β on the day of treatment. This study has demonstrated the responsiveness of the pituitary gland by LH release to different doses of GnRH in 4.5-month-old prepubertal gilts.     

Methodology for the study of the hypothalamic-pituitary hormone secretion in cattle

Studies on the neuroregulatory mechanisms on the secretion of anterior pituitary (AP) hormones in domestic animals are important because nearly all complex physiological and metabolic processes are regulated by the AP hormones. To examine them, this article considers in vivo approaches such as the techniques of intrahypothalamic injection, intracerebroventricular injection, push-pull perfusion, and microdialysis, which have been employed in our own research group for the study in cattle. Also, in vitro approaches such as bovine AP cell culture and the AP explants superfusion system are described. This article clarifies the potential of neuroendocrine study techniques in cattle.     

猪垂体细胞单层培养

本研究建立了猪垂体前叶细胞单层培养模型 ,并进行了免疫细胞化学研究。结果显示 ,用 0 2 5 %胶原酶 ,0 0 5 %透明质酸酶和 0 0 1%DNA酶消化垂体前叶 2次 ,每个垂体可获 5× 10 8个细胞 ,细胞活率在 90 %以上。用含 10 %小牛血清的McCoy’s 5A培养液培养 2 0h ,细胞贴壁 ,4 0h左右形成单层 ,形成单层后换无血清培养液仍维持生长。抗LH和FSH免疫细胞化学染色表明 ,大多数LH阳性细胞同时也是FSH阳性细胞。在单层细胞中 ,LH和FSH阳性细胞占细胞总数的比例不足 10 %。本培养模型可用于体外研究垂体细胞的功能及调控     

DETERMINATION OF OPTIMAL WINDOW WIDTH AND LEVEL FOR MEASUREMENT OF THE CANINE PITUITARY GLAND HEIGHT ON COMPUTED TOMOGRAPHIC IMAGES USING A PHANTOM

The purpose of this study was to determine the optimal window level and width for accurate measurement of pituitary gland height in a phantom. A phantom, mimicking the appearance of the pituitary gland, was made by using the base of a canine skull immersed in buttermilk. Seven different-sized cylindrical pieces of cheese were made and the real diameter of each sample was measured by using a caliper. The cheese was then placed in the pituitary fossa, and 2-mm thick contiguous computed tomography (CT) slices were acquired. The height of the cheese was measured using electronic calipers with different window width and level (WW-WL) settings. The mean difference between CT and manual caliper measurements and concordance correlation coefficients were calculated for all settings. CT measurements underestimated manual caliper measurements with all settings, but the smallest difference (0.5 mm) was obtained with a 250-80 window. Concordance coefficients ranged from 0.699 to 0.820, with the maximum concordance coefficient obtained with a 250-80 window. A second series of measurements using a different window setting for the brain-pituitary gland edge (WW-WL: 250-80) and for the bone-pituitary gland edge (WW-WL: 250-240) resulted in a reduction in the mean difference (0.1 mm) and an increase in the concordance coefficient (0.836). It was concluded that underestimation of the height of the pituitary gland on CT images is most likely due to erroneous placement of the edge of the basisphenoid bone using a low level and a narrow window.     

MENSURATION OF THE NORMAL PITUITARY GLAND FROM MAGNETIC RESONANCE IMAGES IN 96 DOGS

The pituitary gland was measured from transverse magnetic resonance T1-weighted images after Gadolinium administration in 96 dogs weighing from 13 to 45 kg. The measurements were done by hand with calipers. The mean (+/- standard deviation) pituitary gland height was 5.1 mm (+/-0.9 mm). The mean width was 6.4 mm (+/- 1.1 mm). The correlation coefficient between pituitary and brain measurements, between pituitary measurement and body weight, and brain measurements and body weight was 0.0 to 0.3. A hyperintense region was present on T1-weighted images in the center of the pituitary gland in 64% of the dogs. At necropsy the pituitary glands were grossly and histologically normal. No pituitary gland measurements were performed at necropsy.     

MAGNETIC RESONANCE IMAGING FINDINGS IN 15 ACROMEGALIC CATS

Feline acromegaly is characterized by chronic excessive growth hormone secretion, most commonly caused by a functional pituitary adenoma. In this study, acromegaly was diagnosed in 15 cats on the basis of compatible clinical signs, laboratory, and magnetic resonance imaging (MRI) findings. MRI findings were reviewed retrospectively. Enlargement of the pituitary gland with suprasellar extension was present in all cats. No characteristic signal patterns were identified on T1‐weighted and T2‐weighted sequences. Contrast enhancement was nonuniform in all cats, as was suspected involvement of the adjacent hypothalamus. A mass effect on the cavernous sinus and third ventricle was present in 13 cats. Mild peritumoral edema was present in four cats, and moderate edema in one cat. Transtentorial herniation was present in one cat. Histopathology confirmed the presence of a pituitary adenoma in two cases. MRI is a useful modality to establish the diagnosis of acromegaly.     

Persistent Bilateral Mydriasis Associated With a Pituitary Adenoma in a Horse

Severe bilateral mydriasis and bilaterally decreased vision were observed in a 23-year-old crossbred warmblood gelding with a history of pituitary pars intermedia dysfunction. Ten years after the onset of clinical signs, it was killed humanely because of worsening of clinical signs and loss of therapeutic responsiveness. Postmortem examination of the head was performed to confirm the suspected pituitary neoplasm and to investigate secondary oculomotor lesions. Pathomorphologic examination revealed an expansile space-occupying pituitary adenoma and degenerative changes in the preganglionic oculomotor nerve, ciliary ganglion, and optic chiasm. The ocular clinical findings share features of a cavernous sinus syndrome.     

体外无血清培养牛垂体细胞分泌催乳素的调节—性腺激素的作用

本实验对牛垂体混合细胞进行24小时体外无血清培养,对其分泌催乳素的功能进行了观察,并分别在培养介质中加入0、1、10、100ng/ml的孕酮、脱氢表雄酮、雄烯二酮、雌二醇和睾酮,用放射免疫测定法测定培养液介质中催乳素含量,以研究这些性腺激素和中间产物对垂体细胞分泌催乳素的影响。结果表明:孕酮对离体牛垂体细胞无血清培养条件下分泌催乳素的功能没有影响。而脱氢表雄酮、雄烯二酮、睾酮和雌激素均引起催乳素分泌量显著升高,说明这些性腺类固醇激素对牛垂体细胞离体培养分泌催乳素具有促进作用,可能是垂体前叶催乳素分泌调节的重要组成部分。     

Pituitary gland abscess in a horse subsequent to head trauma

A 5-year-old Thoroughbred gelding with recent history of head trauma presented with multiple facial swellings, bilateral mucopurulent nasal discharge, neck pain, inappetence and depression. On computed tomographic examination, lesions within the pituitary fossa and structures adjacent to the right guttural pouch were identified. Soft tissue swelling was seen in the dorsal aspect of the right guttural pouch surrounding several cranial nerves, with fluid-like material in the dependent portions of the right guttural pouch. A CSF sample revealed mild mixed pleocytosis and increased protein concentration. The horse had concurrent periapical disease of the 209-cheek tooth and mild left sinusitis. The horse's demeanour deteriorated requiring euthanasia. Post-mortem examination revealed a pituitary gland abscess.     

COMPARISON OF TWO COARSE FRACTIONATED RADIATION PROTOCOLS FOR THE MANAGEMENT OF CANINE PITUITARY MACROTUMOR: AN OBSERVATIONAL STUDY OF 24 DOGS

Radiotherapy is a commonly used treatment for pituitary macrotumors in dogs, but the optimum protocol has not been established. Twenty four dogs with MRI confirmed pituitary macrotumors were treated with one of two radiotherapy protocols. Twelve dogs were treated with 10 fractions of 3.8 Gy/fraction on a “Monday–Wednesday–Friday” schedule, the remaining 12 with five “once‐a‐week” protocols (1 × 5 Gy, followed by 4 × 8.25 Gy) to a total dose of 38 Gy. The overall median survival time for all dogs was 235 days (range 28–1,328), dogs treated with 10 fractions had a median survival time of 961 days (range 28–1,328) compared to 182 days (range 42–507) in the five‐fraction group (P = 0.006). Clinical improvement was found in both groups, and no significant side effects were noted in either group. These results suggest that a “Monday–Wednesday–Friday” schedule may improve survival times, as compared to a “once‐a‐week” protocol. As this study was of an observational nonrandomized nature, future work is necessary to establish whether more highly fractionated protocols or different total doses will further improve outcome.     

Thyroid Dysplasia in Wistar Hannover GALAS Rats

Thyroid dysplasia was recognized in WistarHan GALAS rats and confirmed as a heritable congenital disorder. The gene or genes involved were not identified, but homozygous animals with thyroid dysplasia also exhibited stunted growth, had reduced pituitary gland growth hormone (GH) and were hypothyroid. Heterozygous animals exhibited thyroid dysplasia with normal thyroid hormonal homeostasis and no difference in the incidence of preneoplastic or neoplastic lesions in oncogenicity studies.     

瘦素在生殖调节方面的研究进展

瘦素是一种由Leptin(ob)基因编码并主要由脂肪组织合成分泌的蛋白质类激素，广泛存在于各组织、器官中。其在调节机体脂肪和保持体重方面具有重要作用。对它的最初的研究主要集中在肥胖的作用，但以后的研究结果发现其缺乏不是造成单纯肥胖的原因。有研究表明，瘦素亦可作为一种代谢信号对下丘脑－垂体－性腺轴发挥功能。     

发情期和乏情期哈萨克羊垂体差异表达基因筛选及功能预测

垂体是哺乳动物重要的内分泌器官之一,主要通过调控激素合成来调节动物发情。为了研究绵羊垂体系统在发情状态和乏情状态之间的基因表达差异,本研究使用RNA-seq技术分析了发情期和乏情期哈萨克羊垂体前叶的转录组数据。通过比较转录组数据发现:在发情期和乏情期的哈萨克羊垂体中共筛选出了3 211个差异表达的基因,其中包含298个上调的和2 913个下调的基因。利用GO和KEGG富集分析这些差异表达的基因发现:它们被显著地富集在卵母细胞减数分裂和孕酮介导的卵母细胞成熟等调控发情的信号通路上,提示这些基因在调控哈萨克羊发情状态中发挥着不可或缺的作用。本研究丰富了绵羊的转录组资源,为今后深入研究绵羊季节发情机制、提高绵羊繁殖率打下了良好的基础。     

HSD17B12基因对湖羊垂体细胞促性腺激素合成的影响

旨在探索湖羊垂体中17β-羟类固醇脱氢酶12（HSD17B12）基因对垂体激素分泌的影响。本研究挑选体重相近（40 kg左右）且健康的性成熟湖羊公羊（9月龄）3只，采集垂体组织进行HSD17B12基因CDS区扩增及蛋白同源性分析，确定其CDS区序列。利用免疫组化分析HSD17B12在性成熟雄性湖羊垂体中的表达定位。体外分离湖羊垂体细胞，利用RNA干扰和细胞转染技术体外干扰HSD17B12，qPCR鉴定激素相关基因的表达水平，并利用流式细胞仪检测细胞增殖、凋亡、周期等的变化。结果表明，HSD17B12基因CDS区长度为939 bp，并且在物种间保守性较高。此外， HSD17B12在湖羊垂体组织大部分细胞中均呈现阳性表达。在垂体细胞干扰HSD17B12后，可以造成细胞增殖效率显著降低（P<0.05），细胞凋亡比率显著增加（P<0.05），细胞周期发生显著改变（P<0.05），且垂体促性腺激素合成相关基因FSHβ、LHβ和生长激素基因GH表达水平均显著降低（P<0.05）。结果提示，在湖羊垂体细胞中干扰HSD17B12的表达，可通过影响细胞增殖、周期和凋亡水平的变化而显著降低促性腺激素及生长激素的分泌。本研究初步证明了HSD17B12基因在湖羊垂体中的重要作用，为进一步探索其中的作用机制提供一定的基础。     

Orexin‐B‐like immunoreactivity in pituitary αMSH‐producing cells and median eminence GnRH‐containing fibres of the flat‐tailed house gecko

We examined the distribution of the orexin‐like peptides in the pituitary and median eminence of the flat‐tailed house gecko (Hemidactylus platyurus) using immunohistochemistry. Orexin‐B‐like, but not orexin‐A‐like, immunoreactivity was detected in the pituitary, specifically in the pars intermedia, and these cells corresponded to alpha‐melanocyte‐stimulating hormone (αMSH)‐producing cells. Orexin‐B and αMSH secreted from pars intermedia may modulate secretion of adenohypophyseal cells in the pars distalis. In the median eminence, orexin‐B‐immunoreactive puncta and fibres were observed, and these structures corresponded to gonadotropin‐releasing hormone (GnRH)‐immunoreactive puncta and fibres. Orexin‐B secreted from GnRH‐containing neurons in the hypothalamus may affect thyrotropin‐releasing hormone‐containing neurons resulting in modulation of αMSH secretion of melanotrophs in the pars intermedia.     

Pituitary–adrenal axis function in dogs with neoplasia*

Adrenocorticotropic hormone (ACTH) stimulation tests were done in healthy and tumour‐bearing dogs. In the tumour‐bearing dogs, plasma endogenous ACTH (eACTH) concentration was measured and adrenal gland size was assessed ultrasonographically. Measurements in the tumour‐bearing dogs were taken prior to therapy. No difference existed in basal or ACTH‐stimulated cortisol concentration between tumour‐bearing and healthy dogs. No difference existed in eACTH concentration between dogs with non‐haematopoietic neoplasia (NHN) and lymphoma. However, of 20 dogs with lymphoma, 15% had increased basal serum cortisol concentration, 5% had an exaggerated response to ACTH and 5% had an increased eACTH concentration. Of 15 dogs with NHN, 20% had increased basal cortisol concentration, 7% had an exaggerated ACTH response and no dogs had an increased eACTH concentration. Of the dogs with lymphoma and NHN, 5 and 13%, respectively, had decreased basal cortisol concentrations; 20% of dogs with lymphoma and 13% with NHN had a subnormal ACTH response. eACTH levels were below the reference range in 10% of dogs with lymphoma and 7% with NHN. Overall, 10 adrenal glands were enlarged in seven dogs, five with lymphoma and two with NHN. The clinical significance of these findings remains to be determined.