Plasma 17-Hydroxycorticosteroid Levels and Leucocyte Values in the Rhesus Monkey, Including Normal Variation and the Effect of ACTH

Abstract

In 36 rhesus monkeys plasma 17-hydroxycorticosteroid levels in morning samples averaged 37.7 [plus or minus] 1.3 [mu]g/100 ml. Leucocyte counts averaged 14,000 [plus or minus] 870, of which 7250 [plus or minus] 700 were polymorpho-nuclear and 6390 [plus or minus] 470 were lymphocytes. Eosinophil counts averaged 390 [plus or minus] 50. Volume of packed red cells averaged 48.1 [plus or minus] 0.53%. In all these determinations the variation of morning values for a given animal was smaller than that for the sp. Rhythmic variations in plasma 17-hydroxycorticosteroid levels and eosinophils were shown to occur within a 24-hour cycle. Steroid levels were maximal around 6 a.m., fell sharply until 9 a.m., then fell gradually during the day until the nocturnal rise begins around 9 p.m. Average eosinophil counts were more variable but did show a maximum during the night and minimum during the morning. Total leucocyte, polymorphonuclear, and lymphocyte counts showed no clear-cut 24-hour rhythm. These findings closely resemble the results of similar studies in man and dog. The rhesus monkey responded to ACTH with a rise in plasma 17-hydroxycorticosteroid level and a drop in eosinophil count comparable to those found in man.