Abstract

The overall aims are to define the basic effects of gonadal steroids, the effects of patterns of gonadal steroids, and the interactions of seasonal effects and gonadal steroids on LHRH and LH patterns in the male using the ram as a model.
The specific aims are: 1. To define the effect of season on LHRH and LH pulse relationships and test the null hypotheses that LHRH secretory patterns and LHRH-LH relationships do not change with season. LHRH and LH pulse parameters will be analyzed at 3 phases of the annual reproductive cycle. 2. To test the null hypothesis that the major gonadal steroids (testosterone and estrogen) do not alter LHRH pulse parameters in the male. The effects of constant physiological concentrations of testosterone and estrogen, alone and combined, on LH and LHRH pulse parameters will be determined. 3. To test the hypothesis that episodic delivery of testosterone is more effective in altering LHRH and LH pulse parameters than is constant delivery. The effects of the two modes of delivery will be compared. 4. To test the hypothesis that the pattern of testosterone pulses affects the patterns of LHRH and LH pulses. Initially, the effects of symmetrical, evenly spaced T pulses will be compared with the effects of symmetrical, unevenly spaced T pulses.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD027453-03
Application #
3329125
Study Section
Reproductive Biology Study Section (REB)
Project Start
1991-01-01
Project End
1994-07-14
Budget Start
1993-01-01
Budget End
1994-07-14
Support Year
3
Fiscal Year
1993
Total Cost
Indirect Cost

  Institution

Name
University of Illinois Urbana-Champaign
Department
Type
Schools of Veterinary Medicine
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820

  Publications

Jackson, G L; Wood, S G; Kuehl, D E (2000) A gamma-aminobutyric acidB agonist reverses the negative feedback effect of testosterone on gonadotropin-releasing hormone and luteinizing hormone secretion in the male sheep. Endocrinology 141:3940-5
Hileman, S M; Jackson, G L (1999) Regulation of gonadotrophin-releasing hormone secretion by testosterone in male sheep. J Reprod Fertil Suppl 54:231-42
Lubbers, L S; Hileman, S M; Kuehl, D E et al. (1998) Temporal effects of estradiol (E) on luteinizing hormone-releasing hormone (LHRH) and LH release in castrated male sheep. Domest Anim Endocrinol 15:511-24
Ferreira, S A; Hileman, S M; Kuehl, D E et al. (1998) Effects of dialyzing gamma-aminobutyric acid receptor antagonists into the medial preoptic and arcuate ventromedial region on luteinizing hormone release in male sheep. Biol Reprod 58:1038-46
Ferreira, S A; Browning, D A; Scott, C J et al. (1998) Effect of infusing gamma-aminobutyric acid receptor agonists and antagonists into the medial preoptic area and ventromedial hypothalamus on prolactin secretion in male sheep. Endocrine 9:303-12
Ferreira, S A; Scott, C J; Kuehl, D E et al. (1996) Differential regulation of luteinizing hormone release by gamma-aminobutyric acid receptor subtypes in the arcuate-ventromedial region of the castrated ram. Endocrinology 137:3453-60
Rhim, T J; Schaeffer, D J; Jackson, G L (1993) Comparison of the effects of pulsatile and constant testosterone on the secretion of gonadotropins in the ram. Endocrinology 132:2399-406
Rhim, T J; Kuehl, D; Jackson, G L (1993) Seasonal changes in the relationships between secretion of gonadotropin-releasing hormone, luteinizing hormone, and testosterone in the ram. Biol Reprod 48:197-204
Jackson, G L; Kuehl, D; Rhim, T J (1991) Testosterone inhibits gonadotropin-releasing hormone pulse frequency in the male sheep. Biol Reprod 45:188-94