Chronobiological study of pituitary adenomas and of the empty sella syndrome.

A chronobiological study was carried out in pituitary GH- and PRL-secreting adenomas and in the empty sella syndrome. The circadian rhythms of plasma GH and plasma PRL were abolished respectively in GH- and PRL-secreting pituitary tumors, and they were again detectable after selective transsphenoidal adenomectomy. In the empty sella syndrome only the chrono-organization of GH secretion was disturbed, whereas plasma PRL exhibited the usual circadian pattern. A normal circadian rhythmicity of plasma cortisol was demonstrable in the 3 groups of patients. The diagnostic significance of the chronobiological findings obtained is discussed.