Androgen and progesterone effects on follicle-stimulating hormone and luteinizing hormone secretion in anestrous mares.
Abstract: Anestrous lighthorse mares were treated in December with dihydrotestosterone (DHT; 150 micrograms/kg of body weight), progesterone (P; 164 micrograms/kg), both DHT and P (DHT+P), testosterone (T; 150 micrograms/kg), or vehicle (n = 4/group). Daily blood sampling was started on Day 1, and on Day 4 all mares were administered a pretreatment injection of gonadotropin-releasing hormone (GnRH) and were bled frequently to characterize the responses of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) concentrations. Treatment injections were given on Day 4 and then daily through Day 17. On Day 18, all mares were again administered GnRH and were bled frequently. Treatment of mares with DHT, P, or T increased (p less than 0.01) plasma concentrations of these steroids to approximately 1.5 ng/ml during the last 10 days of treatment. There was no effect (p greater than 0.10) of treatment on LH or FSH concentrations in daily blood samples. Relative to the pretreatment GnRH injection, mares treated with T or DHT+P secreted approximately 65% more (p less than 0.01) FSH in response to the post-treatment GnRH injection; FSH response to the second GnRH injection was not altered (p greater than 0.10) in control mares or in DHT- or P-treated mares. There was no effect of any steroid treatment on LH secretion after administration of GnRH (p greater than 0.10). Averaged over all mares, approximately 94 times more FSH than LH was secreted in response to injection of GnRH.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1986-02-01 PubMed ID: 3082376DOI: 10.1095/biolreprod34.1.51Google Scholar: Lookup
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- Journal Article
Summary
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The research investigates the impact of certain hormones on how anestrous (non-ovulating) mares (female horses) secrete two other hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), following treatment with gonadotropin-releasing hormone (GnRH). The results suggest that certain treatments can influence the FSH response but not the LH response to GnRH administration.
Research Methodology and Treatment Groups
- The experiment involved anestrous lighthorse mares which were put into different groups and treated with various hormones (DHT, P, DHT+P, T) or a vehicle control-substance. There were 4 mares in each group.
- Every day from Day 1, blood samples were collected from the mares.
- On Day 4, all the mares were given a pre-treatment injection of GnRH. Blood was drawn regularly to examine the changes in FSH and LH concentrations.
- On Day 18, all mares were again administered GnRH and blood samples were collected frequently.
Observations from the Experiment
- After treatment, the mares who received DHT, P, or T had increased plasma concentrations of those hormones, approximately to 1.5 ng/ml, during the last 10 days of treatment.
- There were no significant effects seen from the treatment on LH or FSH concentrations in daily blood samples.
FSH and LH Responses after Gonadotropin-Releasing Hormone (GnRH) Injection
- Those mares that were treated with T or DHT+P secreted about 65% more FSH in response to the post-treatment GnRH injection, as compared to their response to the pre-treatment GnRH injection.
- The FSH response to the second GnRH injection was not altered significantly in mares treated with DHT or P, or the control group.
- No effect was observed on LH secretion, regardless of the steroid treatment given, following administration of GnRH.
- Averaged out for all mares, around 94 times more FSH than LH was secreted in response to an injection of GnRH.
Cite This Article
APA
Thompson DL, Garza F, Ashley KB, Wiest JJ.
(1986).
Androgen and progesterone effects on follicle-stimulating hormone and luteinizing hormone secretion in anestrous mares.
Biol Reprod, 34(1), 51-57.
https://doi.org/10.1095/biolreprod34.1.51 Publication
Researcher Affiliations
MeSH Terms
- Anestrus / drug effects
- Animals
- Dihydrotestosterone / pharmacology
- Drug Interactions
- Estrus / drug effects
- Female
- Follicle Stimulating Hormone / blood
- Follicle Stimulating Hormone / metabolism
- Gonadotropin-Releasing Hormone / pharmacology
- Horses / physiology
- Kinetics
- Luteinizing Hormone / blood
- Luteinizing Hormone / metabolism
- Progesterone / pharmacology
Citations
This article has been cited 1 times.- Kent MG, Schneller HE, Hegsted RL, Johnston SD, Wachtel SS. Concentration of serum testosterone in XY sex reversed horses. J Endocrinol Invest 1988 Sep;11(8):609-13.
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