Repeated observations have demonstrated that adult men have higher values than women for red blood cell count, hemoglobin, and hematocrit.1,2 More recently it has been shown that the total red cell volume of the human male exceeds that of the female.
These differences are apparently not caused solely by iron deficiency, pregnancy, or menstrual blood loss.3 Such statistically valid sexual differences, the changes of which are most pronounced during the period of greatest sexual activity,2 suggest that erythropoiesis and the elaboration of sex hormones are intimately related. Further correlations of blood volume with lean body mass measurements will be helpful in defining such influences.
These phenomena have also been reported in many species of mammals and in fowl. Animal experimental work has been extensive but difficult to interpret. The removal of many endocrine glands induces an anemia which disappears when the lacking hormone is supplied.4 Vollmer
GARDNER FH, PRINGLE JC. Androgens and ErythropoiesisI. Preliminary Clinical Observations. Arch Intern Med. 1961;107(6):846–862. doi:10.1001/archinte.1961.03620060046007
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