Abstract
Abstract
Anterior pituitary hyperplasia was developed in female Fisher 344 rats by subcutaneously implanted slow-release diethylstilbestrol (DES) capsules. Blood flow was measured in two separate areas of the adenohypophysis using hydrogen clearance method at 6, 9, 10, and 13 weeks after the implantation. Blood flow progressively decreased while the DES capsules were in place (normal values in ml/g/min, mean ± SD: 0.93 ± .12 laterally and 1.15 ± .11 medially, decreasing to 0.25 ± .07 and 0.24 ± .07, respectively, by 13 weeks). Histology confirmed nodular hyperplasia, development of large vascular lakes, and hemorrhages within the adenohypophysis. Total adenohypophysial blood flow was calculated as a product of mean blood flow as measured per unit weight and the weight of the gland. This figure progressively increased from 12.7 ± 2 to 22.2 ± 8 μl/min by 13 weeks. All these changes were significant at the P < 0.001 level. These blood flow measurements suggest that the hyperplastic adenohypophysis outgrows its blood supply which is additionally compromised by “useless” pooling of blood in the vascular lakes. However, there is an overall increase in the amount of blood flowing through the hyperplastic gland which may be explained by newly formed supplying vessels.
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