μ-and m-calpain expression and activity changes following diethylstilbestrol injection in the rat anterior pituitary

Little is known about changes in calpain activity in the pituitary gland. In the present study,μ- and m-calpain activity changes were detected in the rat anterior pituitary following intraperitoneal injection of diethylstilbestrol. Double-immunofluorescence labeling confirmed colocalization of μ- and m-calpain in prolactin-secreting cells （lactotrophs）. Western blot analysis revealed significantly increased expression of both calpains, which accompanied upregulated cytosol and membrane zymographic activities at 12 weeks following diethylstilbestrol injection, compared with rats injected with sunflower oil. Moreover, following estrogen injection, pituitary gland pathological damage gradually worsened with increasing time. Results demonstrated that estrogen regulated calpain expression and activity, and both calpains participated in the pathophysiological processes of the pituitary gland. Ubiquitous calpain expression could serve as an effective target for anti-estrogen drugs.

Influence of leptin on luteinizing hormone and follicle stimulating hormone secreted from cultured rat anterior pituitary cells

BACKGROUND： Leptin may regulate reproductive function via release of hypothalamic neuropeptide Y. However, it is unknown whether this regulatory effect is limited to the hypothalamus. OBJECTIVE： To detect the effect of different dosages of leptin on luteinizing hormone （LH） and follicle stimulating hormone （FSH） secretion from in vitro cultured rat anterior pituitary cells. DESIGN： Contrast study based on cells. SETTING： This study was performed in the Basic Institute of Chengde Medical College, Chengde City, Hebei Province, China from March to June 2007. MATERIALS： Eighteen female Wistar rats of three months of age, weighing 200-220 g, and of clean grade were used. Leptin was provided by Peprotech Company, DMEM culture medium by Invitrogen Company, and the radioimmunological kit by Beijing Zhongshan Jinqiao Biotechnology Co., Ltd. METHODS： Three glandular organs were regarded as one group for culture of anterior pituitary cells. In the control group, saline was added to the culture medium instead of leptin. In the leptin group, leptin was prepared into different concentrations of 1×10^-12, 1×10^-11, 1×10^-9, 1×10^-7, and 1×10^-6 mol/L for stimulation of cultured cells. The culture supernatant was obtained at three hours after additional of saline/leptin. MAIN OUTCOME MEASURES： Contents of LH and FSH were detected by radioimmunology. RESULTS： Following leptin stimulation, LH release increased with increasing concentrations of leptin up to 1×10^-9 mol/L, where LH release peaked. LH release then progressively decreased with increasing leptin concentrations （P 〈 0.01）. LH release in the leptin （1×10^-12, 1×10^-11, 1×10^-7, and 1×10^-6 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. FSH content in the leptin （1×10^-11, 1×10^-9, and 1×10^-7 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. CONCLUSION： Leptin can directly affect pituitary tissue to promote the secretion of LH and FSH in a dose-dependent manner.

FOLLICULO-STELLATE CELLS OF THE RAT ANTERIOR PITUITARY RESPONDED TO ANGIOTENSIN Ⅱ BY INCREASING INTRACELLULAR Ca^(2+) CONCENTRATION

Objective The main purpose of this study was to investigate whether the folliculo stellate cells (FSC) respond to angiotensin(Ang)Ⅱ by increasing intracellular free Ca 2+ concentration ([Ca 2+ ]i),and where the origin of Ca 2+ mobilization is if that has occurred.Methods Pituitary cells in primary culture were prepared from male Wister rats(250g) by a conventional method and cultured in MEM supplemented with 4% normal rat serum.After 2 days in culutre,cells were loaded with 1 μmol/L fura PE3/AM for 1 h and subjected to a Ca 2+ imaging experiment with Quanti Cell 700 system.Excitation wavelengths of 340 and 380 nm were selected by means of a computer controlled filterwheel.Results The [Ca 2+ ]i of FSC in the rat anterior pituitary was elevated by Ang Ⅱ.The elevation of [Ca 2+ ]i of FSC induced by 0.1,1.0,10 and 100 nmol/L Ang Ⅱ was (56.33±6.18)( ±s ),(117.07±36.07),(175.59±40.01) and (216.02±11.52) nmol/L,respectively.The increase of [Ca 2+ ]i of FSC induced by 100 nmol/L Ang Ⅱ was not influenced by the medium without Ca 2+ (0Ca),but significantly suppressed by thapsigargin(TG),an inhibitor of ATPase.The rate of responsive FSC to Ang Ⅱ (100 nmol/L) was 61.84% which was obviously higher than that of pituitary endocrine cells(43.49%).Conclusion The present experiment demonstrates that the FSC in the rat anterior pituitary responds to Ang Ⅱ by increasing [Ca 2+ ]i,which raises the possibility that Ang Ⅱ released from either lactotrophs or gonadotrophs affects FSC through paracrine mechanism.The elevation of [Ca 2+ ]i induced by Ang Ⅱ presents a dosage dependent relation, and is possibly because of the release of Ca 2+ from an intracellular Ca 2+ pool(s).Fashions of Ca 2+ release are relative to the concentration of Ang Ⅱ.The results indicate that Ang Ⅱ functions as a paracrine factor among pituitary cells including FSC.

Rehabilitation of anterior pituitary dysfunction combined with extrapontine myelinolysis: A case report

BACKGROUND Extramedullary myelinolysis is a rare demyelinating disease, often caused by rapid increases in serum sodium concentration in patients with hyponatremia.Clinical manifestations are neuropsychiatric symptoms, limb weakness, and dysarthria. Because of its poor prognosis and high disability rate, it poses a huge burden on the global economy, societies, and families. This article reports rehabilitation in a patient with pituitary dysfunction combined with extramedullary myelinolysis.CASE SUMMARY A 27-year-old Chinese man developed anorexia, vomiting, and limb weakness and was diagnosed with pituitary insufficiency. He had low serum sodium, slow movement, muscle weakness, and muscle tone abnormalities after sodium supplementation, involuntary limb shaking, ataxia, and dysarthria. According to the symptoms and signs and imaging reports, he was diagnosed with extramedullary myelinolysis. After treatment with hormone therapy and neurotrophic drugs, motor and speech function did not improve, so he was treated in the rehabilitation department for 4 wk. The patient's physical status was improved substantially during his stay at the rehabilitation department.CONCLUSION Patients with extramedullary myelinolysis who actively participate in rehabilitation intervention can significantly improve their activities of daily living.

Functional magnetic resonance imaging evaluation of visual cortex activation in patients with anterior visual pathway lesions

The aim of this study was to examine the secondary visual cortex functional disorder in patients with glaucoma and large pituitary adenoma by functional magnetic resonance imaging, and to determine the correlation between visual field defect and primary visual cortex activation. Results showed that single eye stimulation resulted in bilateral visual cortex activation in patients with glaucoma or large pituitary adenoma. Compared with the normal control group, the extent and intensity of visual cortex activation was decreased after left and right eye stimulation, and functional magnetic resonance imaging revealed a correlation between visual field defects and visual cortex activation in patients with glaucoma and large pituitary adenoma. These functional magnetic resonance imaging data suggest that anterior optic pathway lesions can cause secondary functional disorder of the visual cortex, and that visual defects are correlated with visual cortex activation.