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

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed 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 Lincoln, G. A. Articles by Jabbour, H. N. Search for Related Content PubMed PubMed Citation Articles by Lincoln, G. A. Articles by Jabbour, H. N. Agricola Articles by Lincoln, G. A. Articles by Jabbour, H. N.

Prolactin Actions in the Sheep Testis: A Test of the Priming Hypothesis

^a MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, Edinburgh EH3 9ET, United Kingdom

ABSTRACT

This study investigated whether prolactin (PRL) plays a priming role in the testis during the nonmating season and thereby facilitates gonadal reactivation. Sexually inactive Soay rams under long days were treated as follows: 1) group C (control) received vehicle, 2) group B received bromocriptine to suppress PRL secretion, 3) group B + PRL received bromocriptine + ovine PRL to reinstate physiological levels of PRL (n = 5/group). Treatments were for 10 wk. The photoperiod was then switched to short days to reactivate the reproductive axis. Testis diameter and sex skin coloration were recorded, and routine blood samples were collected to measure concentrations of FSH, inhibin A, and testosterone (T). At the end of the treatments, blood samples were collected every 10 min for 10 h to monitor LH pulses and the T-response to exogenous LH, and a testis biopsy was collected to assess spermatogenic activity (bromodeoxyuridine [BrDU] method) and expression of PRL receptor (reverse transcription-polymerase chain reaction and immunocytochemistry). There were no significant differences between groups in spermatogenesis (BrDU index) or steroidogenesis (T-response), and no difference in the time taken to achieve full testicular redevelopment under short days. Testis diameter and inhibin A were marginally increased in group B + PRL. Overall, this thorough experiment provides minimal support for the priming hypothesis.

FOOTNOTES

First decision: 4 April 2001.

¹ Correspondence: G.A. Lincoln, MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, 37 Chalmers Street, Edinburgh EH3 9ET, UK. FAX: 44 0 131 228 5571; g.lincoln{at}hrsu.mrc.ac.uk

This article has been cited by other articles:

				A. Bartke Prolactin in the Male: 25 Years Later J Androl, September 1, 2004; 25(5): 661 - 666. [Full Text] [PDF]

				W.M. Hair, F. C.W. Wu, and G. A. Lincoln An investigation of the effectiveness of testosterone implants in combination with the prolactin inhibitor quinagolide in the suppression of spermatogenesis in men Hum. Reprod., April 1, 2003; 18(4): 749 - 755. [Abstract] [Full Text] [PDF]

				H. Jimenez-Severiano, J. Quintal-Franco, V. Vega-Murillo, E. Zanella, M. E. Wehrman, B. R. Lindsey, E. J. Melvin, and J. E. Kinder Season of the year influences testosterone secretion in bulls administered luteinizing hormone J Anim Sci, April 1, 2003; 81(4): 1023 - 1029. [Abstract] [Full Text] [PDF]

				W.M. Hair, O. Gubbay, H.N. Jabbour, and G.A. Lincoln Prolactin receptor expression in human testis and accessory tissues: localization and function Mol. Hum. Reprod., July 1, 2002; 8(7): 606 - 611. [Abstract] [Full Text] [PDF]