エストロゲン

1. In order to study the effect of diethylstilbestrol (DES) injections on growth and fat deposition in White Leghorn male chicks, DES was injected into breast muscle each other day at levels of 0.1, 0.5, and 1.0 mg in 0.25 ml of olive oil for various period. Three trials were conducted. Chicks of 60 days of age were injected with DES and slaughtered after 20 days (Group A) and 60 days (Group BII) ; 90 days old chicks were treated for 30 days (Group BI) ; some chicks of Groups BI and BII were continuously injected for 80 days (Groups CI and CII). Under these conditions the effects of DES injections on chicks were as follows. 2. DES injection caused growth depression in chicks of Group A, and growth stimulation in Group BI. The difference of growth response between both groups was attributed to the different status of formation and deposition of body fat in the chicks. 3. Abdominal adipose leaf developed, corresponding to DES levels administered. The liver was enlarged on the high level of DES (Group A) or long term treatment (Group C). Thyroid showed slightly reducing tendency of the weight in Groups A and BI, and an increasing tendency in Group C. The weight of adrenal showed no definite change, and that of the anterior pituitary was little affected by DES injections. 4. During the treatment of DES injections neutral fat was increased in adipose leaf and skin, leg muscle, and then internal organs, except liver, in which phospholipid increased in some degree in Groups A and B, moreover added neutral fat considerably by long term treatment(Group C). Phospholipid and cholesterol content of the other tissues was affected a little, but variably. 5. Fattening effect of DES injections was not followed by lipemia response, nor marked increase of liver lipid (Groups A and 13). Lipemia response was first noticed in Group C, and the magnitude of the blood-lipid leve0l was variable with DES injection levels. 6. It appeared that the deposition of fat in the adipose tissue and muscle tissue was affected differently in relation to DES levels (Groups A and B). Although stored fat of the skin and abdominal adipose leaf was increased considerably on lower levels of DES injections, fat deposition in the leg muscle was inferior to that injected with high DES level, on which the fat deposition in the former was lesser than that with lower DES levels (Groups A and BI). Increase of the muscle fat was obtained on high DES level (Groups A and BI) or by longer treatment on lower DES level (Group BII). 7. There was age effect on the rate of fat deposition. Younger chicks (Group A) were able to deposit more fat in the body than did older chicks (Group BI) on the same levels of DES. 8. Fat was much more deposited in the body with longer administration of DES on low level than with shorter administration of DES on higher level, when the same amount of DES was administered. 9. The weight of abdominal adipose leaf was increased, corresponding to the level of DES injected. The weight of the tissue which has been used as an index of the fattening effect by DES, was not always parallel to the amount of fat deposited in carcass (Groups A and B). 10. Although the whole amount of fat d e posited in carcass was affected by DES levels, it was distributed 9-12 % of the total fat in visceral organs, 11-32% in adipose tissues (abdominal adipose leaf and skin), and 59-80 % in the residual carcass, in which muscle formed the main structural substance. Therefore, the principal change of fat distribution in the whole carcass was represented by the relative change within the adipose tissue and residual carcass or muscle, which was related to the DES level administered. The proportional ratio of the former was increased by DES injection of lower level, and that of the latter by the injection of higher level. It was suggested that the fat o f adipose and muscle tissue represented the separate types of lipid and different threshold dosage of DES would exist for fat deposition in them, alike that observed for lipemia and fattening responses.