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The Contributions of Adrenal Hormones, Hemodynamic Factors, and the Endotoxin‐Related Stress Reaction to Stable Prostaglandin Analog‐Induced Peripheral Lymphopenia and Neutrophilia
Author(s) -
Ulich Thomas R.,
Keys Marcy,
Ni RongXiang,
Castillo Juan del,
Dakay Edwin B.
Publication year - 1988
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.43.1.5
Subject(s) - neutrophilia , captopril , endocrinology , medicine , dexamethasone , prostaglandin , prostaglandin e2 , adrenalectomy , biology , pharmacology , blood pressure
Abstract Stable prostaglandin analogs are known to induce lymphopenia and neutrophilia in a dose‐dependent fashion after subcutaneous injection in rats. The purpose of the present investigation is to determine whether the prostaglandin‐induced changes in circulating leukocytes might be secondary to hypotension with the ensuing release of adrenal hormones. The adrenal medullary catecholamine epinephrine was found to induce neutrophilia in both intact and adrenalectomized rats, and the glucocorticosteroid analog dexamethasone induced a profound lymphopenia in rats as reported by previous investigators. A stable analog of PGF 2α (15‐S‐15‐methyl PGF 2α ; M‐PGF 2α ) at the dose of 1 mg/kg induced marked systemic hypotension 1 h after injection, with lymphopenia and neutrophilia 6 h after injection. The non‐prostanoid hypotensive agent captopril, at a dose of 63 mg/kg, induced a hypotension of similar magnitude and kinetics to that induced by prostaglandin. Captopril also induced lymphopenia and neutrophilia at 6 h, although the neutrophilia was of lesser magnitude than that induced by prostaglandins. The prostaglandin‐induced lymphopenia was found to be mediated, at least in part, by the hypotension‐induced release of adrenal hormones, as evidenced by the abrogation of lymphopenia in prostaglandin‐treated adrenalectomized rats. Captopril‐treated adrenalectomized rats, however, did develop a significant lymphopenia, suggesting that hypotension can result in lymphopenia even in adrenalectomized rats. The M‐PGF 2α ‐induced neutrophilia in adrenalectomized rats, by comparison to captopril‐induced neutrophilia in adrenalectomized rats, was greater than the neutrophilia expected as the result of hypotension alone. Indeed, the M‐PGF 2α ‐induced neutrophilia in adrenalectomized rats was greater than the captopril‐induced neutrophilia in sham‐adrenalectomized rats. Thus, a portion of the neutrophilia induced by M‐PGF 2α in intact rats may be mediated through adrenal‐independent, hemodynamic‐independent mechanisms. The possibility that M‐PGF 2α might be inducing neutrophilia via an endotoxin‐like stress reaction was investigated by examining changes in circulating white blood cells in intact and adrenalectomized C3H/HeN (endotoxin‐sensitive) and C3H/HeJ (endotoxin‐resistant) mice after prostaglandin administration. No quantitative differences in the prostaglandin‐induced neutrophilia were noted in C3H/HeJ mice as compared to the C3H/HeN mice. In conclusion, the effects of M‐PGF 2α on circulating white blood cells in the intact rat are mediated in part through hemodynamic and adrenal mechanisms, and in part through adrenal‐independent, hemodynamic‐independent, and endotoxin‐like stress reaction‐independent mechanisms. Prostaglandins may contribute directly to the genesis of neutrophilia.