REGULATION OF B-CELL AND T-CELL DEVELOPMENT BY ANTERIOR-PITUITARY HORMONES

Hormones produced by the anterior pituitary gland have been implicated in the regulation of primary lymphocyte development. In order to iden tify endocrine factors involved in that process, several strains of mi ce with genetic defects resulting in a selective impairment in the pro duction of one or more anterior pituitary-derived hormones have been a nalysed. This study has resulted in the classification of endocrine ho rmones into the following four categories: (i) hormones such as prolac tin with no apparent effects on primary lymphopoiesis; (ii) anabolic h ormones such as growth hormone and insulin-like growth factor-I whose stimulatory effects on primary lymphopoiesis are non-lineage-specific and related to their actions as systemic mediators of growth and/or di fferentiation; (iii) hormones such as thyroid hormones that have an ob ligate role in primary B lymphopoiesis; and (iv) hormones such as oest rogens that act as negative regulators of lymphopoiesis.