Seasonal variation in platelet 3H-imipramine binding: Comparable values in control and depressed populations

Diurnal and Circannual Variation in Platelet ³H-Imipramine Binding: Comparative Data on Normal and Affectively Ill Subjects

“…Circannual variation in Bmax has been observed in both depressed and normal control populations with no change in Kd [Egrise et al, 1983;Whitaker et al, 1984;Hrdina et al, 1985]. The biorhythm noted by Whitaker et al [1984] corresponded to the seasonal variation reported by other investigators [Wirz-Justice and Rich ter, 1979;Swade and Coppen, 1980] in platelet serotonin uptake.…”

“…In accord with Lewis and McChesney [1985] our data do not support either one of the opposing biorhythms noted by Egrise et al [1983] and Whitaker et al [1984], However, for the following reasons these results must be interpreted with caution. First, our measurements were cross-sectional, an approach considered less informative than the prospective longitudinal design that aims to measure both intraindividual and interindividual varia tions.…”

“…The biorhythm noted by Whitaker et al [1984] corresponded to the seasonal variation reported by other investigators [Wirz-Justice and Rich ter, 1979;Swade and Coppen, 1980] in platelet serotonin uptake.…”

“…While Egrise et al [1983] found maximal values of Bmax in September and minimal val ues in the spring, Whitaker et al [1984] observed lower Bmax values in September and higher values in January. The data of Hrdina et al [1985] showed further discrep ancy: these authors reported maximal Bmax values in August through October and minimal values in winter time.…”

“…As discussed [Mellerup et al, 1984;Baron et al, 1986], this variability has been attributed to nonuniform selection and diagnostic procedures, variation in assay methodol ogies, drug effect, and biological heterogeneity. More recently the possibility that circannual, or seasonal ef fects contribute to the variable results has been raised [Egrise et al, 1983;Whitaker et al, 1984;Hrdina et al, 1985]; however, the data are scarce and contradictory. Further impetus for assessing temporal changes in 3H-IMI binding stems from reports on the seasonal nature of a subset of affective disorders [Rosenthal et al, 1984].…”