HOME HELP CONTACT US 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 Wong, C. C. Articles by von zur Mühlen, A. Search for Related Content PubMed Articles by Wong, C. C. Articles by von zur Mühlen, A.

Seasonal effects were studied on basal levels of hormones in the serum of adult male Sprague–Dawley rats, which were born and raised under rigorously controlled laboratory conditions. Groups of 90-day-old rats were killed at monthly intervals by rapid decapitation. Significant fluctuations were observed throughout the observation period of 19 months in serum levels of TSH, prolactin, androgens, tri-iodothyronine and LH. Minor fluctuations were observed in serum levels of FSH, corticosterone, parathyroid hormone and thyroxine. The results indicate that male laboratory rats exhibit circannual and semi-annual fluctuations in serum levels of several hormones even though the animals were born, raised and maintained in constant laboratory conditions.

This article has been cited by other articles:

				A. Kalsbeek, R. M. Buijs, R. van Schaik, E. Kaptein, T. J. Visser, B. Z. Doulabi, and E. Fliers Daily Variations in Type II Iodothyronine Deiodinase Activity in the Rat Brain as Controlled by the Biological Clock Endocrinology, March 1, 2005; 146(3): 1418 - 1427. [Abstract] [Full Text] [PDF]

				M. S. Marty, J. W. Crissman, and E. W. Carney Evaluation of the Male Pubertal Assay's Ability to Detect Thyroid Inhibitors and Dopaminergic Agents Toxicol. Sci., March 1, 2001; 60(1): 63 - 76. [Abstract] [Full Text] [PDF]

				M. Karasek, A. Lewinski, and L. Vollrath Precise Annual Changes in the Numbers of "Synaptic" Ribbons and Spherules in the Rat Pineal Gland J Biol Rhythms, March 1, 1988; 3(1): 41 - 48. [Abstract] [PDF]