N. W. Kasting

Evidence supporting a role for endogenous vasopressin in natural suppression of fever in the sheep.

1. The antipyretic effect of arginine vasopressin (AVP) introduced into the brain by push‐pull perfusion was investigated in the sheep. 2. Control perfusions with sucrose solutions had no effect on fevers induced by a bacterial endotoxin. Sucrose solutions containing AVP (4.0 microgram/ml.) perfused at 40 microliter./min had significant antipyretic activity, reducing the two peaks of the fever but had no effect on resting body temperature. 3. Loci in which AVP induced antipyresis were limited to the septal region about 2‐3 mm anterior to the anterior commissure. 4. The amounts of AVP in perfusates from the septal region correlated negatively with changes in body temperature. 5. AVP administered I.V. did not lower fever. 6. AVP plasma levels correlated negatively with fever magnitude following premature birth induced by dexamethasone.

[10] Push—pull perfusion technique in the median eminence: A model system for evaluating releasing factor dynamics

Publisher Summary The chapter presents the push-pull perfusion technique of the median eminence (ME) combined with chronic atrial catheterization of the rat, a valuable tool for investigating dynamic changes in secretion of hypophysiotropic factors and subsequent release of pituitary hormones. This technique has allowed making some preliminary observations on secretion of somatostatin (SS) in the unanesthetized rat. This technique has the potential of allowing much better understanding of the temporal patterns of hypophysiotropic factor secretion and consequently more precise knowledge about the interaction of these factors to regulate anterior pituitary hormone release into plasma. The push-pull perfusion technique combined with chronic intra-atrial catheterization could be used to determine temporal patterns of SS release in the ME and its relationship to the plasma levels of the anterior pituitary hormone that it regulates—namely, growth hormone (GH).