Tibia Weight Research Articles

Prevention of experimental bone atrophy by thyrocalcitonin.

In order to study the effect of thyrocalcitonin on experimental bone atrophy, male Wistar rats were placed on low calcium diet and given prednisol one twice a week. Thyrocalcitonin administered in a dose of 50 MRC milliunits in a single subcutaneous injection daily caused an increase of cortical thickness of the femur and tibia and slight increase in the weight of tibia and specific gravity of both bones, but calcium and phosphorus content failed to show a marked change. Upon incubation of the metaphysis and diaphysis of the femur in Krebs Ringer bicarbonate buffer p H 7.4 containing 45Ca at 37°Cfor 1 hr., a significant inhibition of 45Ca uptake by the metaphysis of the femur was seen in thyrocalcitonin-treated rats. Maximal weight before breaking upon bending stress was also increased in thyrocalcitonin treated rats. These findings are consistent with the preventive effect of thyrocalcitonin on experimental bone atrophy probably through inhibition of bone resorption.

EFFECTS OF A PITUITARY HOMOTRANSPLANT AND THYROXINE ON BODY AND MAMMARY GROWTH IN IMMATURE HYPOPHYSECTOMIZED RATS.

Hypophysectomized, immature female rats, approximately 65 g in body weight, were implanted subcutaneously with a single anterior pituitary from 3- to 4-monthold female rats of the same strain, and were not treated further or were injected with thyroxine for 30 days. The effects on body and tail growth, mammary development and weight of several organs were measured. Hypophysectomized rats given a single pituitary transplant only, or a pituitary transplant together with thyroxine, exhibited body weight gains equal to 46.6 and 75.5 %, respectively, of that of intact controls. Tail length, tibial cartilage width, and spleen and thymus weights were all significantly greater in the rats with a pituitary transplant; addition of thyroxine resulted in a further increase in body weight, tail length and in spleen and thymus weight. No effects of the pituitary transplant or thyroxine were observed on the atrophic ovaries, uterus or adrenals. In contrast to the atrophic mammary glands of the hypophysectomized control ...

Studies on the effect of hormone administration on body weight and on tibial epiphysial cartilage width in intact, hypophysectomized and adrenalectomized rats.

SUMMARY 1. The effects of feeding, hormone administration, unilateral nephrectomy and adrenalectomy on width of tibial cartilage and total body weight in intact and hypophysectomized young male rats were measured. 2. Unilateral nephrectomy and adrenalectomy have no effect on the cartilage width of both intact and hypophysectomized rats, although adrenalectomy causes a loss in weight in the intact rat. 3. Intact rats, both young and adult, fed enough to maintain but not to put on weight, show a reduction of cartilage width to hypophysectomized levels. 4. Growth hormone alone (1 mg. and 3 mg./day for 14 days) causes a marked increase in cartilage width but only a 50–60% increase in total body weight in the hypophysectomized rat. 5. Adrenocorticotrophin (ACTH: 2 i.u./day for 14 days) causes a significant reduction in both cartilage width and total body weight in the hypophysectomized rat. 6. Thyrotrophin (TSH: 1 i.u./day) and Prolactin (1 mg. and 2 mg./day) caused significant increases in both total body weight and cartilage width in the hypophysectomized rat. 7. Luteinizing hormone (LH: 0·01 mg./day) together with follicle stimulating hormone (FSH: 1·0 mg./day) caused a significant increase in body weight, but had no effect on cartilage width in the hypophysectomized rat. 8. Both doses of combined hormones (growth hormone, ACTH, TSH, prolactin, FSH and LH administered together) caused a marked increase in cartilage width and a smaller increase in total body weight in the hypophysectomized rat.

Immunological investigations on bovine pituitary growth hormone.

The antigenicity of highly purified bovine pituitary growth hormone was studied by means of anaphylactic shock experiments in guinea pigs, precipitin ring tests with rabbit antisera, and bioassay of the antiserum in hypophysectomized rats for antihormone activity. Bovine growth hormone in the adjuvant, Bayol-Ai-lacel, was found to be antigenic in guinea pigs and rabbits. Furthermore, as little as 1 µg. of growth hormone could be detected by the precipitin test, using rabbit antiserum which was absorbed free of certain non-specific antibodies. This antiserum did not react with any of the other anterior lobe hormones tested at comparable and considerably higher doses. The absorbed antiserum was found to be capable of inhibiting the stimulation of tibial epiphyseal cartilage and body weight gain effected in hypophysectomized rats by growth hormone.