Melatonin secretion decreases during the proestrous stage of the rat estrous cycle.
Urine was collected from rats during 12 consecutive daily dark periods and assayed for melatonin and norepinephrine; the phase of the vaginal estrous cycle associated with each urine sample was determined from daily vaginal smears. The proestrous phase of the estrous cycle was consistently associated with significant reductions in the excretions of both compounds. The level of melatonin in any urine sample tended to vary as a function of its norepinephrine content; however, the slope of the curve relating these two compounds in metestrous-diestrous samples differed from that for proestrous-estrous specimens. This difference suggests that factors other than the catecholamine (e.g., gonadal hormones) also affect melatonin secretion. Oophorectomy elevated the melatonin concentration of serum but not that of the pineal; this rise was suppressed by the administration of estrogen plus progesterone. The fate of circulating melatonin (as indicated by the proportion of an exogenous dose excreted into the urine) was not affected by the state of the estrous cycle.
D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D004971:Estrus; D005260:Female; D008550:Melatonin / Q000378:metabolism* / Q000652:urine; D009638:Norepinephrine / Q000652:urine; D010870:Pineal Gland / Q000378:metabolism*; D011247:Pregnancy; D011359:Proestrus; D011374:Progesterone / Q000494:pharmacology; D051381:Rats
D011374:Progesterone; D004958:Estradiol; D008550:Melatonin; D009638:Norepinephrine
Annu Rev Pharmacol Toxicol. 1976;16:33-51
180879
Science. 1977 Feb 18;195(4279):686-7
841305
Neuroendocrinology. 1976;22(1):89-96
1035969
Res Commun Chem Pathol Pharmacol. 1975 Apr;10(4):693-702
1057224
Endocrinology. 1976 Jun;98(6):1418-24
1084276
Science. 1975 Jan 17;187(4172):169-71
1167425
J Clin Endocrinol Metab. 1975 Feb;40(2):347-50
1168857
Endocrinology. 1976 Feb;98(2):482-9
1248456
Endocrinology. 1970 Sep;87(3):527-33
4316487
Endocrinology. 1970 Jul;87(1):1-12
4392758
Biol Reprod. 1974 May;10(4):474-9
4477971
Endocrinology. 1973 Jan;92(1):333-5
4734140
Science. 1970 Sep 11;169(3950):1093-5
4915470
Life Sci I. 1971 Jul 15;10(14):791-5
5112235
Nature. 1968 Mar 9;217(5132):953-4
5300432
Gen Comp Endocrinol. 1970 Oct;15(2):334-8
5478661
Acta Physiol Scand. 1961 Apr;51:348-55
13697529
Biochim Biophys Acta. 1960 Sep 23;43:352-3
13784117
Science. 1960 Apr 29;131(3409):1312
13795316
Science. 1963 Jul 19;141(3577):277-8
14002083
J Pharmacol Exp Ther. 1962 Dec;138:360-75
14013351
Science. 1964 Mar 20;143(3612):1328-30
14113619
J Biol Chem. 1965 Feb;240:949-54
14275158
Endocrinology. 1965 Apr;76:798-800
14289208
J Biol Chem. 1961 Nov;236:3072-5
14458327
Science. 1966 Feb 18;151(3712):825-6
17746729