Stallion endocrinology

The table below summarizes the hormones in the stallion.

Hormone	Source	Target	Effect
GnRH	hypothalmus	anterior pituitary	Release of LH Release of FSH
LH	anterior pituitary	Leydig cells	Production of testosterone
FSH	anterior pituitary	Sertoli cells	Production of inhibin and estradiol
Testosterone	Leydig cells	hypothalmus	Negative feedback on GnRH secretion (thus LH and FSH)
Testosterone	Leydig cells	Sertoli cells	Production of estradiol
Estradiol	Sertoli cells	hypothalmus	Negative feedback on GnRH secretion (thus LH and FSH)
Inhibin	Sertoli cells	anterior pituitary	Suppress FSH secretion
Androgen Binding Protein (ABP)	Sertoli cells		A testosterone transport protein
Oxytocin	posterior pituitary	muscle	contraction of vas deferens and pelvic urethral muscle