Morphologic and biochemical changes in male rat lung after surgical and pharmacological castration

The morphology of the rat lung was studied by light microscopy in different situations: after surgical and pharmacological castration and after administration of testosterone to the castrated rat to determine if the androgen is required to maintain the normal morphology of the lung. We also determined the effect of flutamide on the phospholipid composition of both the surfactant and microsomes of the lung. Rats were separated into five groups: I - control non-castrated rats, II - castrated rats sacrificed 21 days after castration, III - castrated rats that received testosterone daily from day 2 to day 21 after castration, IV - castrated rats that received testosterone from day 15 to day 21 after castration, and V - control rats injected with flutamide for 7 days. The amount of different phospholipids in the surfactant and microsomes of the lung was measured in group I and V rats. At the light microscopy level, the surgical and pharmacological castration provoked alterations in the morphology of the lung, similar to that observed in human lung emphysema. The compositions of surfactant and microsomes of the lung were similar to those previously reported by us for the surgically castrated rats. These results indicate that androgens are necessary for the normal morphology as well as for some metabolic aspects of the lung.

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

The neuroendocrine system regulates several organic functions such as reproduction, metabolism and adaptation to the environment. This system shows seasonal changes linked to the environment. The experimental model used in the present study was Lagostomus maximus maximus (viscacha). The reproduction of males of this species is photoperiod dependent. Twenty-four adult male viscachas were captured in their habitat at different times during one year. The adrenal glands were processed for light microscopy. Serial cuts were stained with hematoxylin-eosin for the morphometric study, and 100 nuclei of each zone of the adrenal cortex were counted per animal. Data were analyzed statistically by ANOVA and the Tukey test. The cells of the glomerulosa zone are arranged in a tube-shaped structure. The fasciculata zone has large cells with central nuclei and clearly visible nucleoli and with a vacuolar cytoplasm. In the reticularis zone there are two of types of cells, one with a nucleus of fine chromatin and a clearly visible nucleolus and the other with nuclear pycnosis. Morphometric analysis showed maximum nuclear volumes during the February-March period with values of 133 percet 7.3 µm3 for the glomerulosa, 286.4 percent 14.72 µm3 for the fasciculata, and 126.3 percent 9.49 µm3 for the reticularis. Minimum nuclear volumes were observed in August with values of 88.24 + or - 9.9 µm3 for the glomerulosa, 163.7 percent 7.78 µm3 for the fasciculata and 64.58 + or - 4.53 µm3 for the reticularis. The short winter photoperiod to which viscacha is subjected could inhibit the adrenal cortex through a melatonin increase which reduces the nuclear volume as well as the cellular activity

Estudio bioquímico-histológico de los efectos de litio en algunos organos de vizcacha (Lagostomus maximus maximus) / Biochemical-histological study of the effects of lithium in some organs of vizcacha (Lagostomus maximus maximus)

Considerando que la vizcacha (lagostomus maximus maximus) es un roedor muy sensible al Litio (Li), planificamos un estudio bioquímico-histológico inyectando cloruro de Li 1 mEq/Kg/día vía intraperitoneal durante un mes a vizcachas adultas de ambos sexos agrupadas en tres lotes. En el lote I se comprobó por técnicas de microscopía óptica un evidente dano renal, gonodal, hipofisario y adrenal; por métodos bioquímicos se comprobó que el Li disminuyó significativamente los niveles séricos de LH en hembra, el contenido de testosterona y estradiol no fue modificado. En machos el Li sérico resultó significativamente mayor (p<0.01, Prueba de t) que en hembras. El dano fue mayor en machos. en el Lote II se estudió a 30 días de la última administración el grado de recuperación tisular del dano comprobado en el Lote I. Se verificó una recuperación total en hipófisis, parcial en testículo, nula en rinón y se incrementó el dano en adrenal y ovario. Con respecto al efecto seletivo sobre la zona glomerulosa adrenal del Li sería producido via hipófisis. En conclusión el efecto selectivo de Li en adrenal y gónadas en este roedor es una contribución para alertar sobre la posible producción de estos efectos en humanos

Biological role of the pineal.Responses to the environmental photoperiod.

La pineal de la vizcacha (Lagostomus maximus maximus) sacrificadas durnate invierno muestra caracteristicas citologicas de un organo activo. En esta estacion el animal se encuentra adaptado a un prolongado medio ambiente de oscuridad. Sus organos reproductores estan inactivos.Durante el verano la viscacha tiene su ciclo anual reproducto y la pineal esta aparentemente inactiva. Estos cambios estacionales de la glundula pineal pueden relacionarse con el fotoperiodo natural y con la exposicion gradual a la luz crepuscular durante los periodos de luz diarios del verano. Dicha informacion fotica podria expresarse como cambios en el tono simpatico pineal. Las pineales de vizcacha y rata podrian tambien influjir sobre la secrecion de la pars intermedia hipofisaria, las que responderian como fotorreceptores en el mecanismo de adaptacion al fotoperiodo natura