title: Morning to evening changes of human pituitary and adrenal responses to specific stimuli.
abstract: We performed a combined stimulation test with the simultaneous application of GnRH (100 micrograms), TRH (200 micrograms) and ACTH (10 micrograms) in 10 healthy adult males at two opposite clock timing, i.e. at 09:00 and 21:00 h. Pituitary (gonadotropins, PRL, TSH) and adrenal (cortisol, aldosterone, progesterone) hormones showed a common trend of enhanced responsiveness to the evening challenge. Differences reached statistical significance in the case of cortisol, aldosterone, PRL and FSH. These findings suggest that the responsiveness of some pituitary and adrenocortical hormones to specific stimuli is physiologically different in humans as a function of the clock timing, being higher in the evening than in the morning. From the clinical standpoint, however, differences in the magnitude of responses were not enough to recommend provocative testing at a particular clock time, at least for routine diagnostic purposes.
authors.affiliation: Dipartimento di Biomedicina, Univesità degli Studi di Torino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Terzolo
authors.forename: A
authors.initials: A
authors.lastname: Piovesan
authors.forename: G
authors.initials: G
authors.lastname: Osella
authors.forename: B
authors.initials: B
authors.lastname: Puligheddu
authors.forename: M
authors.initials: M
authors.lastname: Torta
authors.forename: P
authors.initials: P
authors.lastname: Paccotti
authors.forename: A
authors.initials: A
authors.lastname: Angeli
mesh_terms: D000311:Adrenal Glands / Q000502:physiology*; D000324:Adrenocorticotropic Hormone; D000328:Adult; D000450:Aldosterone / Q000097:blood; D002940:Circadian Rhythm; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010902:Pituitary Gland / Q000502:physiology*; D011388:Prolactin / Q000097:blood; D013973:Thyrotropin-Releasing Hormone
chemical_list: D007987:Gonadotropin-Releasing Hormone; D000450:Aldosterone; D013973:Thyrotropin-Releasing Hormone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D005640:Follicle Stimulating Hormone; D006854:Hydrocortisone