Influence of psoralen on NAT activity and melatonin levels in rat pineal gland during the daily period of darkness

K. Li, G. M. Vaughan, Russel J Reiter

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A single injection of either 5 or 10 mg/kg 8-methoxypsoralen (8-MOP) was given intraperitoneally to male rats at the end of the 14 h light phase (at 2000 h). Two h later (at 2200 h), when the normal nocturnal surge of N-acetyltransferase (NAT) activity and melatonin content in the pineal gland had begun in vehicle-injected controls, mean pineal NAT after the 10 mg/kg 8-MOP was 1.8-fold higher than that after vehicle, though pineal malatonin content did not differ between vehicle- and drug-injected rats. By 4 h into the dark period (at 2400 h), the NAT activity in both 8-MOP injected groups of rats was greater than that in vehicle treated animals; again, however, 8-MOP treatment did not influence the pineal melatonin content. At 0200 h (6 h into the dark period), the difference between the NAT activity in pineals of rats treated with 5 mg/kg 8-MOP and the vehicle was not statistically significant, but the animals that received 10 mg/kg drug still had statistically elevated levels of the serotonin acetylating enzyme. At 0200 h the pineal melatonin levels were equivalent among the three treatment groups. Rats given 5 mg/kg 8-MOP always had NAT values intermediate between those of rats injected with vehicle and those that received 10 mg/kg 8-MOP suggesting that the NAT response to the drug was dose related. These results show that the pineal response to psoralen involves an elevation of NAT activity without a commensurate change in the melatonin content of the gland.

Original languageEnglish (US)
Pages (from-to)43-48
Number of pages6
JournalEndocrine Research
Volume13
Issue number1
StatePublished - 1987

Fingerprint

Methoxsalen
Ficusin
Acetyltransferases
Pineal Gland
Darkness
Melatonin
Pharmaceutical Preparations
Serotonin
Light
Injections
Enzymes
Therapeutics

ASJC Scopus subject areas

  • Endocrinology

Cite this

Influence of psoralen on NAT activity and melatonin levels in rat pineal gland during the daily period of darkness. / Li, K.; Vaughan, G. M.; Reiter, Russel J.

In: Endocrine Research, Vol. 13, No. 1, 1987, p. 43-48.

Research output: Contribution to journalArticle

@article{82f2eb55353748ce93097ce517968b79,
title = "Influence of psoralen on NAT activity and melatonin levels in rat pineal gland during the daily period of darkness",
abstract = "A single injection of either 5 or 10 mg/kg 8-methoxypsoralen (8-MOP) was given intraperitoneally to male rats at the end of the 14 h light phase (at 2000 h). Two h later (at 2200 h), when the normal nocturnal surge of N-acetyltransferase (NAT) activity and melatonin content in the pineal gland had begun in vehicle-injected controls, mean pineal NAT after the 10 mg/kg 8-MOP was 1.8-fold higher than that after vehicle, though pineal malatonin content did not differ between vehicle- and drug-injected rats. By 4 h into the dark period (at 2400 h), the NAT activity in both 8-MOP injected groups of rats was greater than that in vehicle treated animals; again, however, 8-MOP treatment did not influence the pineal melatonin content. At 0200 h (6 h into the dark period), the difference between the NAT activity in pineals of rats treated with 5 mg/kg 8-MOP and the vehicle was not statistically significant, but the animals that received 10 mg/kg drug still had statistically elevated levels of the serotonin acetylating enzyme. At 0200 h the pineal melatonin levels were equivalent among the three treatment groups. Rats given 5 mg/kg 8-MOP always had NAT values intermediate between those of rats injected with vehicle and those that received 10 mg/kg 8-MOP suggesting that the NAT response to the drug was dose related. These results show that the pineal response to psoralen involves an elevation of NAT activity without a commensurate change in the melatonin content of the gland.",
author = "K. Li and Vaughan, {G. M.} and Reiter, {Russel J}",
year = "1987",
language = "English (US)",
volume = "13",
pages = "43--48",
journal = "Endocrine Research",
issn = "0743-5800",
publisher = "Informa Healthcare",
number = "1",

}

TY - JOUR

T1 - Influence of psoralen on NAT activity and melatonin levels in rat pineal gland during the daily period of darkness

AU - Li, K.

AU - Vaughan, G. M.

AU - Reiter, Russel J

PY - 1987

Y1 - 1987

N2 - A single injection of either 5 or 10 mg/kg 8-methoxypsoralen (8-MOP) was given intraperitoneally to male rats at the end of the 14 h light phase (at 2000 h). Two h later (at 2200 h), when the normal nocturnal surge of N-acetyltransferase (NAT) activity and melatonin content in the pineal gland had begun in vehicle-injected controls, mean pineal NAT after the 10 mg/kg 8-MOP was 1.8-fold higher than that after vehicle, though pineal malatonin content did not differ between vehicle- and drug-injected rats. By 4 h into the dark period (at 2400 h), the NAT activity in both 8-MOP injected groups of rats was greater than that in vehicle treated animals; again, however, 8-MOP treatment did not influence the pineal melatonin content. At 0200 h (6 h into the dark period), the difference between the NAT activity in pineals of rats treated with 5 mg/kg 8-MOP and the vehicle was not statistically significant, but the animals that received 10 mg/kg drug still had statistically elevated levels of the serotonin acetylating enzyme. At 0200 h the pineal melatonin levels were equivalent among the three treatment groups. Rats given 5 mg/kg 8-MOP always had NAT values intermediate between those of rats injected with vehicle and those that received 10 mg/kg 8-MOP suggesting that the NAT response to the drug was dose related. These results show that the pineal response to psoralen involves an elevation of NAT activity without a commensurate change in the melatonin content of the gland.

AB - A single injection of either 5 or 10 mg/kg 8-methoxypsoralen (8-MOP) was given intraperitoneally to male rats at the end of the 14 h light phase (at 2000 h). Two h later (at 2200 h), when the normal nocturnal surge of N-acetyltransferase (NAT) activity and melatonin content in the pineal gland had begun in vehicle-injected controls, mean pineal NAT after the 10 mg/kg 8-MOP was 1.8-fold higher than that after vehicle, though pineal malatonin content did not differ between vehicle- and drug-injected rats. By 4 h into the dark period (at 2400 h), the NAT activity in both 8-MOP injected groups of rats was greater than that in vehicle treated animals; again, however, 8-MOP treatment did not influence the pineal melatonin content. At 0200 h (6 h into the dark period), the difference between the NAT activity in pineals of rats treated with 5 mg/kg 8-MOP and the vehicle was not statistically significant, but the animals that received 10 mg/kg drug still had statistically elevated levels of the serotonin acetylating enzyme. At 0200 h the pineal melatonin levels were equivalent among the three treatment groups. Rats given 5 mg/kg 8-MOP always had NAT values intermediate between those of rats injected with vehicle and those that received 10 mg/kg 8-MOP suggesting that the NAT response to the drug was dose related. These results show that the pineal response to psoralen involves an elevation of NAT activity without a commensurate change in the melatonin content of the gland.

UR - http://www.scopus.com/inward/record.url?scp=0023140251&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023140251&partnerID=8YFLogxK

M3 - Article

VL - 13

SP - 43

EP - 48

JO - Endocrine Research

JF - Endocrine Research

SN - 0743-5800

IS - 1

ER -