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 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 Yang, K Articles by Challis, J R G Search for Related Content PubMed PubMed Citation Articles by Yang, K Articles by Challis, J R G

To examine the role of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in the control of glucocorticoid actions in the ovine pituitary during development, we have sought developmental changes in the distribution and the level of 11β-HSD1 mRNA by in situ hybridization. In the pars distalis, 11β-HSD1 mRNA was present by day 60; its amount did not change significantly until term (days 145–147) when it increased dramatically. The level of 11β-HSD1 mRNA increased further during the postnatal period. In contrast, 11β-HSD1 mRNA in the pars intermedia was not detectable until day 135; it increased in amount at days 140–143, but did not change significantly thereafter through to adulthood.

We have also measured levels of both dehydrogenase and reductase activities of 11β-HSD1 in the pars distalis of fetal sheep at day 140 and term, and of postnatal sheep at 1–2 months of age, to determine whether changes in 11β-HSD1 mRNA are reflected in the levels of enzyme activities. There were progressive increases in both dehydrogenase and reductase activities from day 140 to 1–2 months postnatally, although dehydrogenase activity was consistently higher than reductase activity.

Finally, we have determined the effect of short-term intrafetal cortisol infusion (5 µg/min for 12 h) on levels of pituitary 11β-HSD1 mRNA by in situ hybridization. There was no effect of cortisol infusion on 11β-HSD1 mRNA expression.

The present results demonstrate that 11β-HSD mRNA and enzyme activity in the pars distalis of fetal sheep increase dramatically at term when plasma levels of both ACTH and cortisol are elevated. This suggests that 11β-HSD1 may contribute to the proposed resetting of cortisol negative feedback within the fetal pituitary at that time.

This article has been cited by other articles:

				C. W. H. Rumball, M. H. Oliver, E. B. Thorstensen, A. L. Jaquiery, S. M. Husted, J. E. Harding, and F. H. Bloomfield Effects of Twinning and Periconceptional Undernutrition on Late-Gestation Hypothalamic-Pituitary-Adrenal Axis Function in Ovine Pregnancy Endocrinology, March 1, 2008; 149(3): 1163 - 1172. [Abstract] [Full Text] [PDF]

				J. W. Tomlinson, E. A. Walker, I. J. Bujalska, N. Draper, G. G. Lavery, M. S. Cooper, M. Hewison, and P. M. Stewart 11{beta}-Hydroxysteroid Dehydrogenase Type 1: A Tissue-Specific Regulator of Glucocorticoid Response Endocr. Rev., October 1, 2004; 25(5): 831 - 866. [Abstract] [Full Text] [PDF]

				A. C. Holloway, D. C. Howe, G. Chan, V. L. Clifton, R. Smith, and J. R. G. Challis Urocortin: a mechanism for the sustained activation of the HPA axis in the late-gestation ovine fetus? Am J Physiol Endocrinol Metab, July 1, 2002; 283(1): E165 - E171. [Abstract] [Full Text] [PDF]

				M. Korbonits, I. Bujalska, M. Shimojo, J. Nobes, S. Jordan, A. B. Grossman, and P. M. Stewart Expression of 11{beta}-Hydroxysteroid Dehydrogenase Isoenzymes in the Human Pituitary: Induction of the Type 2 Enzyme in Corticotropinomas and Other Pituitary Tumors J. Clin. Endocrinol. Metab., June 1, 2001; 86(6): 2728 - 2733. [Abstract] [Full Text] [PDF]

				W.L. Whittle, F.A. Patel, N. Alfaidy, A.C. Holloway, M. Fraser, S. Gyomorey, S.J. Lye, W. Gibb, and J.R.G. Challis Glucocorticoid Regulation of Human and Ovine Parturition: The Relationship Between Fetal Hypothalamic-Pituitary-Adrenal Axis Activation and Intrauterine Prostaglandin Production Biol Reprod, April 1, 2001; 64(4): 1019 - 1032. [Abstract] [Full Text]

				J. R.G. Challis, S. G. Matthews, W. Gibb, and S. J. Lye Endocrine and Paracrine Regulation of Birth at Term and Preterm Endocr. Rev., October 1, 2000; 21(5): 514 - 550. [Abstract] [Full Text]

				J. Bissonnette, S. Chambers, P. Collins, C. Lockwood, C. Mendelson, L. Myatt, M. L. Polan, W. H. Shen, and S. Szal Strengthening Research in Departments of Obstetrics and Gynecology Reproductive Sciences, May 1, 1997; 4(3): 124 - 129. [Abstract] [PDF]