Inhibitory effect of propranolol on lipid synthesis in gonadectomized male hamster flank organs

Background. This papaer describes the inhibitory effect produced by propanolol pre-treatment on lipid synthesis in flank organs from intact, gonadectomized, and isoproterenol-treated male hamsters. Furthermore, the effect induced by the same treatments on gland sebum composition is reported. Methods. Different groups of male hamsters were injected daily with propranolol, isoproterenol or propranolol plusisoproterenol. Treatment-effect was evaluated determining the in vitro incorporation of radioactive acetate into lipids in hamster flank organs from intact and castrated animals. Additionally, radiolabeled lipids were isolated and identified using TLC and autoradiography as methods. Results. demonstrate that castration significantly decreases lipid synthesis in male hamster flank organs. In addition, propanolol treatment inhibits such synthesis in glands from intact, gonadectomized, and isoproterenol-treated animals. However, isoproterenol treatment was ineffective when compared to intact or gonadectomized control vehicle-treated animals. Lipid classes isolated and identified lipids either in castrated or in drug-treated animals were phospholipids, cholesterol, monoglycerides, fatty acids, waxes and cholesterol esters. Conclusions. Results indicate an inhibitory effect induced on lipid synthesis by ß-adrenergic receptor antagonist; however, ß-adrenergic agonists drugs do not stimulate it. Data suggest a permissive role of adrenergic hormones on lipid synthesis in intact and in gonadectomized animals. Futhermore, castration decreased the synthesis, suggesting that a tight coupling between ß-adrenergic receptors and androgen receptors may be a prerequisite for lipogenesis in this tissue. Pre-treatment does not modify sebum composition in gonadectomized animal glands. These data support the evidence that activation of ß-adrenergic receptors could be an independent factor in the lipid composition regulation process

Influence of fowl uropygial gland and its secretory lipid components on growth of skin surface bacteria of fowl.

Bacterial species, which occur on the breast skin surface of adult (1 year old) white leghorn fowl with intact uropygial gland, were identified as : Staphylococcus epidermidis, Sarcina lutea, Streptomyces sp. and a facultative diphtheroid belonging to the genus Corynebacterium; S. epidermidis being the most predominant one. Two species of bacteria, namely, Staphylococcus aureus and Proteus sp. were shown to colonize the skin surface after 60 days of captivity. Extirpation of uropygial gland caused severe depletion of population of S. epidermidis, Streptomyces sp. and diphtheroid. The effect was more conspicuous after 60 days compared to that after 30 days of the gland removal. On the skin surface of glandless fowls the population of S. aureus increased significantly and a new form identified as anthracoid bacillus became the most predominant species after 60 days. Addition of total lipids from the free-flowing fowl uropygial secretion, as 0.2% suspension, to trypticase soya broth cultures of individual bacteria of fowl skin surface encouraged strongly the growth of S. epidermidis, Streptomyces sp. and Proteus sp. but suppressed the population of the anthracoid. When identical amount of diester wax or wax alcohol of the secretion was supplemented to the culture, more or less similar result was obtained. Wax alcohol also had a mild inhibitory effect on Streptomyces sp. Wax acids, added to the culture (0.2%) suppressed population of all the bacterial forms except Proteus sp., while the hydrocarbon fraction, which also contained some amount of squalene, produce an opposite effect.

Evaluation of levonogestrel action on the flank organ and the sebaceous gland lipogenesis of female hamsters

Se investigaron la función de la testerona y la acción del levonorgestrel sobre el órgano del flanco mediante medición de la lipogénesis de las glándulas sebáceas de hamsters hembras por incorporación metabólica de C-glucosa. Adémas, se obtuvo una caracterización parcial de la fracción lípida radiomarcada. Se evaluaron los efectos de la administración de esteroides in vivo mediante incorporación metabólica de C-U-glucosa en lípidos por los órganos del flanco del hamster hembra en condiciones de cultivo en presencia o en ausencia de LNG, T o ambos en el medio de incubación. Los lípidos radiactivos se identificaron mediante cromatografía de capa delgada. Levonorgesrel, aisladamente o en conjunto con testosterona, disminuyó el peso y el contenido de sebo de los órganos del flanco en el hamster hembra cuando se efectuaron comparaciones con los resultados del tratamiento con T nada más. Cuando se administró T en condiciones de cultivo se Observó un incremento rápido y significativo de la glucosa radiomarcada. En contraste, cuando estaba presente LNG en el medio de incubación, no se observaron diferencias en la incorporación de C-U-glucosa cuando se efectuaron comparaciones con sus controles. Cuando se añadieron T + LNG, se observaron resultados similares a los obtenidos cuando se empleó LNG nada más. La testosterona incrementó las concentraciones de glicéridos y ácidos grados libres, pero disminuyó las de lípidos polares; en contraste, el LNG careciïde efecto sobre las proporciones relativas de incorporación de C-U-glucosa en las diferentes clases de lípidos cuando se efectuaron comparaciones con sus controles. Los resultados indicaron qu el LNG abole el efecto de incremento de la incorporación de C glucosa producido por T y cambia la composición de los lípidos inducida en los órganos del flanco del hamster hembra