Effects of selective pituitary hormone deficiencies on macrophage phagocytic activity in rat (911.2)

Abstract

We showed that neurointermediate pituitary lobectomy (NIL) decreases whereas anterior pituitary lobectomy (AL) increases humoral and cell‐mediated immune responses. Studies indicate that PRL and GH are immune stimulatory/modulatory hormones. Macrophages (Mθ) have receptors for AVP, OXT, PRL and GH. In order to obtain a deeper insight into the role of anterior and posterior pituitary hormones on innate immunity, Mθ phagocytic activity was assessed in NIL, AL, HYPOX, sham operated (SHAM) and Control rats. Carbon black (CB) blood clearance, phagocytic index, CB blood half‐life time (T1/2), and histologic changes in liver, spleen and lung were also studied. Results. CB clearance was faster in SHAM > Control > NIL > HYPOX > AL rats. Differences were noted only in AL with slower clearance, suggesting that adenohypophysial but not neurohypophysial hormones are responsible for the faster CB clearance. Phagocytic index was decreased in NIL rats, indicating that AVP and OXT are required to regulate phagocytic activity. Blood CB T1/2 was 10 minutes in Control and SHAM rats, and 20, 17 and 18 minutes in AL, HYPOX and NIL rats. The longer T1/2 suggests that all pituitary hormones participate in CB clearance. Liver, spleen and lung histology showed Mθ markedly loaded with CB. These findings indicate that adenohypophysial and neurohypophysial hormones participate differently in the regulation of Mθ phagocytic activity.Grant Funding Source: CONACYT MEXICO 62317