HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Morgan, P.J. Articles by Howell, H.E. Search for Related Content PubMed Articles by Morgan, P.J. Articles by Howell, H.E.

Primary cultures of ovine pars tuberalis (PT) cells of the pituitary were established to investigate the mode of action of melatonin. The heterogeneous population of cells was shown to bind the radioligand 2-[¹²⁵I]-melatonin over 72 h in culture, although there was a progressive decline in specific binding with time. In cells cultured for 24 h, forskolin (1 µmol/l) was found to stimulate a 12-fold increase in cyclic AMP accumulation. This response could be inhibited by melatonin in a dose-dependent manner, with an IC₅₀ of approx. 6 pmol/l. However, melatonin did not inhibit basal levels of cyclic AMP.

In homogenates of ovine PT, forskolin stimulated a dose-dependent increase in cyclic AMP, although the magnitude of this response was found to be lower than that observed in cells. This response was not inhibited by either 10 nmol or 1 µmol melatonin/l, and was also unaffected by GTP.

These results provide the first evidence that the melatonin-binding site on ovine PT, recently characterized using the radioligand 2-[¹²⁵I]-melatonin, functions as a physiological receptor.

This article has been cited by other articles:

				J.-L. Guillaume, A. M. Daulat, P. Maurice, A. Levoye, M. Migaud, L. Brydon, B. Malpaux, C. Borg-Capra, and R. Jockers The PDZ Protein Mupp1 Promotes Gi Coupling and Signaling of the Mt1 Melatonin Receptor J. Biol. Chem., June 13, 2008; 283(24): 16762 - 16771. [Abstract] [Full Text] [PDF]

				W. S. Warren, D. B. Hodges, and V. M. Cassone Pinealectomized Rats Entrain and Phase-Shift to Melatonin Injections in a Dose-Dependent Manner J Biol Rhythms, October 1, 1993; 8(3): 233 - 245. [Abstract] [PDF]