<prompt> Diurnal variation in Eosinophil count is related to:CoisolThyroxineGrowth hormoneTestesterone  <response>: A i.e. CoisolDiurnal variation in eosinophilic count is reciprocally invrsely related to circadian levels of coisolQ.- Suprachiasmatic nuclei SCN of hypothalamus is the biological clock responsible for diurnal circadian rhythm of ACTH, which intum leads to diurnal rhythm of coisol glucocoicoid secretion. In humans, ACTH irregular bursts episodes of high secretion are most frequent in early morning and least frequent in the evening. Increased ACTH secretion is not dt stress of getting up in the morning as these bursts occur before waking up. Even if the length of day is experimentally lengthened to 24 hrs ie if the person is isolated and days activities are spread over more than 24h, the adrenal cycle also lengthens, but the ACTH burst still occurs during period of sleep. The circadian rhythm of ACTH secretion is present in patients Eosinophil with adrenal insufficiency receiving constant dose of glucocoicoids.- Coisol decrease the number of circulating eosinophils by increasing their sequestration in the spleen lung. So the diurnal variations in blood eosinophilic counts is inversely related to the circadian coisol levelsQ. The eosinophilic concentration in blood is 450 mL usually. A reciprocal relationship to plasma coisol, causes the diurnal eosinophilic concentrations to vary -- 2 fold 40 with eosinophilic count lowest in morning and peaking in evening. 