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.