Lecture 6: Reproductive Endocrinology of the Adult Male

Question 1

Hypothalamic Activity

Answer 1

formed by hypothalamic nuclei

GnRH neurons are involved with reproduction

to become male; fetal testosterone crosses the blood brain barrier and defeminizes the hypothalamus, so the surge center does not develop

Question 2

GnRH Neurons

Answer 2

extend into the pituitary stalk and terminate on the hypothalamic-hypophyseal portal system

GnRH neurons secrete GnRH in episodic patterns through their terminal ends

GnRH is then captured in the primary portal plexus and transferred to the anterior pituitary through the portal vessels

Negative feedback of steroids on GnRH secretion is done indirectly through pre-synaptic steroid-sensitive neurons