Abstract
Summary
Rats adapted for 2-3 weeks to a fixed schedule of daily feeding exhibited high serum gastrin levels and large increases in serum gastrin after feeding. Serum gastrin was >500 pg/ml throughout most of the 24 hr daily cycle and fell to —∼150 pg/ml 1 hr before the scheduled time of feeding; by 1-2 hr after feeding serum gastrin rose again to >500 pg/ml. This postprandial increase in gastrin was not observed if food was withheld and it was seen also after truncal vagot-omy which itself raised serum gastrin. In contrast, in nonadapted rats serum gastrin was unmeasurable (<20 pg/ml) after a 24 hr fast and rose only to ∼100 pg/ml 1-2 hr after feeding. In nonadapted rats, thyroid-ectomy prevented the 2 hr rise in serum gastrin after feeding. In adapted rats para-thy roidectomy, thyroparathyroidectomy, and thyroidectomy with parathyroid auto-transplantation, all reduced serum gastrin before and after feeding indicating that any surgical intervention with the thyroparathy-roid complex interfered with gastrin release. Rats with autotransplanted parathyroid glands and intact thyroid glands showed a delayed increase in serum gastrin after feeding, as well as a delay in the usual fall in plasma phosphate, 45Ca, and 32P, but if the parathyroids were replaced within the thyroid tissue, this delay did not occur.
The authors appreciate the fine technical assistance of Ms. Dorothy B. Raneri, Mr. Johnny F. Obie and Ms. Blanche P. Holloway. Thanks are expressed to Ms. Merlene Moore for clerical assistance.
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