The effect of endocrinopathies on the blood

Evidence has been presented that the gonads, thyroid, adrenal cortex and pituitary glands have a definite influence on blood formation. The normal sex differencein erythrocyte levels in animals, and probably in man, can be obliterated bycastration and restored by appropriate replacement therapy. Hypothyroidismresults in a moderately severe anemia in animals. In the uncomplicated form, theanemia is slightly macrocytic and associated with a hypoplastic bone marrow.In clinical experience the anemia may be complicated by the secondary effects ofachylia gastrica leading either to iron deficiency or to a deficiency in the antipernicious anemia factor. Hyperthyroidism causes some alterations in the whiteblood cells, but has little effect on the red blood cell series. Hyperactive states ofthe adrenal cortex may be associated with a mild polycythemia. Adrenal steroidsalso have a marked lymphocytic effect, causing the release of beta and gammaglobulins from lymphoid tissue. A mechanism involving the anterior pituitaryand adrenal seems to exist, controlling the release of antibodies under certainconditions. It is suggested that other mechanisms also exist which control thenumber of circulating lymphocytes.

Deficiency of the anterior pituitary secretions results in anemia in animals andman. The anemia in animals is usually microcytic and hypochromic and mayrespond to several types of replacement therapy. In man anemia develops slowlyand is rarely severe. Moderate reductions in the red blood cell count occur andthe color index varies. There is hypoplasia of the bone marrow. The anemia inman does not respond uniformly well to the therapy now available, but improvement often occurs with the replacement of "end-organ" hormones.

The preponderance of evidence indicates that the regulation of blood formationis not primarily under hormonal control. The effects noted in various glandulardisorders are due to alterations in metabolism produced in the bone marrow as wellas all other body tissues.