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Seasonal Changes in Glycogen Level and Size of Pinealocytes of the White‐Footed Mouse, Peromyscus leucopus: A Semiquantitative Histochemical Study
Author(s) -
Kachi T.,
Quay W.B.
Publication year - 1984
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1984.tb00207.x
Subject(s) - peromyscus , pinealocyte , glycogen , biology , circadian rhythm , zoology , pineal gland , endocrinology
Glycogen level in and size of pinealocytes of the feral, white‐footed mouse Peromyscus leucopus , were studied by a semiquantitative histochemical method to determine whether seasonal changes exist in them under natural conditions, what temporal pattern they exhibit, and whether 24‐hour changes in these parameters exist in different seasons, as shown in the laboratory dd‐mice. Marked seasonal changes were seen in both glycogen levels and nuclear densities (ANOVA P < 0.005). The size of pinealocytes at 09:00 to 10:00 showed one peak (and nadir) seasonal change, with the smallest size in winter (December and February) and a larger size in warmer seasons, with the maximum value in July. Glycogen level in pinealocytes at 09:00 to 10:00 showed bimodal seasonal changes, with lower levels in fall and spring and higher levels in winter and summer. In fall, a circadian trend in glycogen level in pinealocytes was seen, with a higher level at the end of the light period. In winter, the glycogen levels were very high at 09:00, 13:00, 17:00, and 21:00 examined and showed dampening of time‐of‐day differences. On the other hand, the size of pinealocytes followed a time‐of‐day change (P < 0.005), being largest at 13:00 and smallest at 21:00. Thus, marked changes in quantitative structure and chemical activities, suggesting changes in functional activity, in pinealocytes were noted especially in severe, cold winter.