Ultrastructural changes in lactotrophs and somatotrophs of alloxan-induced diabetic rats and the possible protective effect of alpha-lipoic acid

Alteration in the cellular composition of the anterior pituitary gland could be involved in both prolactin and growth hormone disturbances in cases of poorly controlled diabetes. This study was conducted to investigate the ultrastructural changes in both somatotrophs and lactotrophs of diabetic rats and to investigate the possible protective effect of alpha-lipoic acid. Thirty adult male rats were randomly divided into three equal groups: group A [control], group B [alloxan-induced diabetic rats], and group C [alloxan-induced diabetic rats that received alpha-lipoic acid]. In rats of groups B and C, diabetes was induced by a single intraperitoneal injection of alloxan monohydrate. In animals of group C, alpha-lipoic acid was given intraperitoneally during the period of the experiment. Twelve weeks after induction of diabetes, specimens of the pituitary gland were processed for transmission electron microscopic examination and a morphometric study was conducted. Somatotrophs of diabetic rats showed condensed nuclei, dilated Golgi saccules, and dilated rough endoplasmic reticulum cisternae. Further, some lactotrophs showed corrugated or condensed nuclei, dilated Golgi saccules, and relatively fewer granules. In both somatotrophs and lactotrophs of diabetic rats, the number of cytoplasmic granules was significantly decreased as compared with that of control rats. In addition, a significant increase in the percentage of empty granules to the total number of granules was recorded. However, the total number of granules and the percentage of empty granules to the total number in both somatotrophs and lactotrophs were significantly reduced in diabetic rats treated with alpha-lipoic acid as compared with untreated diabetic rats. The spectrum of changes in lactotrophs and somatotrophs of uncontrolled diabetic rats was found to be corrected by alpha-lipoic acid and therefore alpha-lipoic acid is recommended as a form of adjuvant therapy for diabetes

Ultrastructural characterization of the pars distalis of the Indian female Sheath-tailed bat, Taphozous longimanus (Hardwicke) / Caracterización ultraestructural de la pars distalis del murciélago cola de vaina hembra indio, Taphozous longimanus (Hardwicke)

The present ultrastructural observations demonstrate the presence of six cell types in the pars distalis of non-pregnant and pregnant bats of Taphozous longimanus. In the pars distalis of T. longimanus, STH cells are round to oval with eccentrically placed nucleus, numerous secretory granules and well developed Golgi indicate a cell under vigorous synthetic activity while those filled with secretory granules with reduced Golgi complex suggest reserve or storage state of cells. LTH cell is characterized by the large secretory granules, dilated endoplasmic reticulum and numerous mitochondria in the cytoplasm which indicate that these cells are hypertrophied and synthetically very active during pregnancy. ACTH cells are found either singly or in groups and are elongated or angular with long cytoplasmic processes. The size and peripheral arrangement of secretory granules are characteristic of ACTH cell. TSH cells are distributed mostly towards the periphery of the pars distalis of T. longimanus. They are elongated, polygonal or triangular in shape. The secretory granules are small, electron dense, 150-200 nm in diameter. The rough endoplasmic reticulum is very well developed. In FSH, the secretory granules are small (200 to 400 nm) and less in number and are distributed towards the periphery of the cell. FSH cells show well developed mitochondria, Golgi and rough endoplasmic reticulum indicating active state of FSH during estrus and pregnancy. The hypertrophy of FSH and LH cells during pregnancy is associated with filigreed cytoplasmic pattern giving a bizarre appearance. At late pregnancy, FSH and LH cells are highly active and synthesize large quantities of hormone as indicated by the development of cell organelles.

Las observaciones ultraestructurales actuales demuestran la presencia de seis tipos de células en la pars distalis de murciélagos Taphozous longimanus preñadas y no preñadas. En la pars distalis del T. longimanus, las células STH son redondas u ovaladas con un núcleo excéntrico, numerosos gránulos de secreción y un Golgi bien desarrollado que indican una célula en actividad de síntesis vigorosa, mientras que las llenas de gránulos de secreción con un complejo de Golgi reducido sugieren un estado celular de reserva o almacenamiento. Las células LTH se caracterizan por grandes gránulos de secreción, el retículo endoplásmico dilatado y numerosas mitocondrias en el citoplasma, indicando que estas células están hipertrofiadas y con una actividad sintética muy activa durante el embarazo. Células de ACTH se encuentran de forma individual o en grupos, son alargadas o angulares, con largos procesos citoplásmicos. El tamaño y la disposición periférica de los gránulos de secreción de ACTH son característicos de la célula. Células de TSH se distribuyen principalmente hacia la periferia de la pars distalis del T. longimanus. Ellos son alargadas, poligonales o de forma triangular. Los gránulos de secreción son pequeños, electrodensos, de 150-200 nm de diámetro. El retículo endoplasmático rugoso está muy bien desarrollado. En células FSH, los gránulos de secreción son pequeños (200 a 400 nm), menores en número y se distribuyen hacia la periferia de la célula. Células FSH muestran mitocondrias bien desarrolladas, Golgi y retículo endoplasmático rugoso que indica el estado activo de la FSH durante el estro y la preñez. La hipertrofia de las células de FSH y LH durante la preñez se asocia con un patrón citoplasmático filigrana dando una extraña apariencia. Al final de la preñez, las células de FSH y LH son muy activas y sintetizan grandes cantidades de hormonas, como producto del desarrollo de las organelos celulares.

Mecanismos de muerte celular que participa en la regresión de los prolactinomas / Cell death mechanisms involved in regression of prolactinomas

El prolactinoma es el tumor más frecuente de la hipófisis y causa una gran morbilidad debido a la hipersecreción hormonal de prolactina (PRL). Rl tratamiento de primera línea es la administración de bromocriptina (BC), un agonista de los receptores dopaminergicos que posee una efectividad de alrededor del 90%. En numerosos estudios clínicos se ha documentado que BC inhibe la transcripción, la síntesis y liberación del PRL y además, suprime la proliferacion e induce la muerte celular provocando la involucción de la masa tumoral. L apoptosis ha sido identificada como un mecanismo de muerte inducido por BC, pero su baja frecuencia no explica la reducción en el tamaño de los prolactinomas. Es por ello que el efecto citotócico de la BC puede disparar otros mecanismos no apoptóticos en las células hipofisarias que serían los principales responsables de la involución del tumor.

Male gonadal function, prolactin secretion and lactotroph population in an experimental model of cirrhosis

Liver cirrhosis, a highly prevalent chronic disease, is frequently associated with endocrine dysfunctions, notably in the gonadal axis. We evaluated lactotroph population by immunohistochemistry, gonadotropins and prolactin by immunoradiometric assay and testosterone and estradiol by radioimmunoassay in adult male Wistar rats with cirrhosis induced by carbon tetrachloride. No significant difference in mean ± SEM percentages of lactotrophs was found between cirrhotic animals and controls (N = 12, mean 18.95 ± 1.29 percent). Although there was no significant difference between groups in mean serum levels of prolactin (control: 19.2 ± 4 ng/mL), luteinizing hormone (control: 1.58 ± 0.43 ng/mL), follicle-stimulating hormone (control: 19.11 ± 2.28 ng/mL), estradiol (control: 14.65 ± 3.22 pg/mL), and total testosterone (control: 138.41 ± 20.07 ng/dL), 5 of the cirrhotic animals presented a hormonal profile consistent with hypogonadism, all of them pointing to a central origin of this dysfunction. Four of these animals presented high levels of estradiol and/or prolactin, with a significant correlation between these two hormones in both groups (r = 0.54; P = 0.013). It was possible to detect the presence of central hypogonadism in this model of cirrhotic animals. The hyperestrogenemia and hyperprolactinemia found in some hypogonadal animals suggest a role in the genesis of hypogonadism, and in the present study they were not associated with lactotroph hyperplasia.

effects acetylsalicylic acid on the pituitary prolactin of the lizard, uromastix hardwickii

This study deals with the intravenous administration of 7mg acetylsalicylic acid [ASA] solution to Uromastix hardwickii for 4 days. It enhances the activity of anterior pituitary lactotrophs, when 0.1 ml of pituitary homogenate of ASA treated was injected hypodermically to crop- sac showed a greater diametric response and increased activity with milk like secretion than that of the injections of 0.1 ml homogenate of control pituitary. The present study indicated that ASA induces hyperprolactinemia

A Case of Drug Induced Nephrogenic Diabetes Insipidus and Hyperprolactinemia in Schizophrenia Simultaneously / 대한내분비학회지

In schizophrenia, when treatment using antipsychotics fails, lithium, which is known as an antimanic drug, can also be administered. It is reported that 12~20% of patients taking lithium develop nephrogenic diabetes lactotrophs. Hyperprolactinemia is induced by typical antipsychotics, as they block the dopamine-2 receptors of latotrophs in the pituitary gland. Therefore, atypical antipsychotics for decreasing the side effect, such as hyperprolactinemia, can be used. However, hyperprolactinemia can be induced by risperidone, one of the atypical antipsychotics. Here, a case of drug induced nephrogenic diabetes insipidus and simultaneous hyperprolactinemia, which occurred in a patient with schizophrenia, is reported.

EGF Enhances the Differentiation Effect of the Extracellular Matrix Components on the GH3 Pituitary Tumor Cell / 대한해부학회지

This study was performed in order to establish the culture system optimal for the study on pituitary prolactin cells using growth factor and extra cellular matrix components as the culture substrate. The effect of epidermal growth factor (EGF) alone or along with extracellular marix components on GH3 cell growth and PRL expression was assessed using cell count, BrdU-immunocytochemistry and PRL-immunocytochemistry in in vitro cultures on plastic, laminin and Matrigel. EGF decreased the cell growth, BrdU-labeling and increased the PRL-immunoreactive cells regardless of the culture substrate by day 3 of the culture. Matrigel was the best culture substrate to decrease the cell growth and to increase the PRL expression. EGF treatment in the Matrigel culture showed about 80.5% of PRL-immunoreactive cells by day 6 of the culture. These results indicated that Matrigel is the better culture substrate than plastic or laminin to inhibit the overgrowth and to increase the prolactin expression of the GH3 cell and that EGF and Matrigel causes very effective culture environment for the long-term culture of the GH3 cell by synergistic mechanism.

Clinical Features of Pityitary Hyperplasia / 대한내분비학회지

BACKGROUNDS: Pituitary hyperplasia can mimic pituitary adenoma. In MRI, enlarged pituitary gland is enhanced homogenously with upward convexity of the superior margin of the gland .The best definition of hyperplasia in the pituitary hyperplasia seems to be a multiplication of one or more cell types. But definition, etiology and clinical courses of this disease are not clear, METHOD: We reviewed clinical symptoms, MRI, and pathologic findindings in 6 patients with pituitary hyperplasia. RESULT: 1. Major clinical symptoms were headache (100%), visual field defect (84%), polyuria/polydipsia (64%), and irregular mensturation (32%). Other symptoms were amenorrhea (16%) and galactorrhea (16%). 2. Three of five cases showed abnormal responses to combined pituitary function test, 3. MRI findings were pituitary hyperplasia (4), macroadenoma (l), and microadenoma (1). 4. In two operated cases, there was no adenoma. One case showed hyperplasia of lactotroph cells, the other was hyperplasia of gonadotroph cells confirmed by the examination of immunocytochemistry. CONCLUSION: Pituitary hyperplasia should be considered in patients with enlarged pituitary gland without focal mass lesion.

Reduction of Central Dopamine Release in Hyperprolactinemia / 대한내분비학회지

Background: Prolactin(PRL) secretion is tonically inhibited by doparnine that originates from the hypothalamic tuberoinfundibular tract and reaches the lactotroph via the hypophyseal portal vessel. Hyperprolactinemia associated with oligomenorrhea-amenorrhea, galactorrhea and/or infertility is mainly due to PRL-secreting pituitary adenoma(PA). The diagnosis of idiopathic hyperprolac- tinemia(IHP) is made, when hyperprolactinemia is sustained and all causes of hyperprolactinemia are excluded without radiological abnormality. It is not known, whether IHP and PA are two distinct entities or two subsequent phases of the same disease. The etiology of both disorders remains unresolved. We investigated that PRL hypersecretion in patients with IHP and PA may be the result of a defect in the central nervous system(CNS)-dopamine release, and that there may be some differences in pathogenesis of both diseases. Methods: We measured 24 hour-urinary dopamine, norepinephrine, epinephrine, and serum and 24 hour-urinary VMA(vanillyl rnandelic acid), HVA(homovanilic acid), DOPAC(3,4-dihydroxy phenylaceticacid), MHPG(3-methoxy 4-hydroxy phenylglycol) in 10 normal controls, 9 patients with IHP, and 17 patients with PA in the early follicular phase. Results: Urinary HVA and DOPAC concentrations, the major metabolites of CNS dopaminergic activity, were signficantly lower in both patients with IHP and PA compared with those in normal controls(p 0.05), whereas they were not different in both disease groups. Dopamine, norepine-phrine, epinephrine, MHPG concentrations were similar to those of the normal controls. Although VMA concentrations of both disease groups were significantly higher than those of normal controls, all of them were within normal range. Conelusion: Although our data are unable to establish the precise biochemical defect responsible for central dopamine deficiency in pathogensis of IHP and PA, we can support the presence of a pathological reduction of brain dopamine activity in IHP and PA.