Abstract
Summary
Anterior pituitaries from lactating and from estrous cyclic hooded Norway rats were cultured simultaneously for 9 days. Lactogen production by pituitaries from lactating rats was slightly greater than that by glands from estrous cyclic rats, but when lactogen production was expressed on a unit weight basis it was significantly greater by pituitaries from estrous cyclic rats. Electrophoretic separation of medium from pituitaries of lactating rats revealed patterns similar to those obtained from medium from pituitaries of estrous cyclic rats. Rate of lactogen production decreased 31.7% from the first 3day culture period to the second 3day culture period, and 14.3% from the second 3day to the third 3day culture period. Evidence was presented which indicated that the decrease in lactogen production with time was due not to a decrease in production rate per se but rather to an increase in anterior pituitary tissue necrosis.
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