Clinical Rounds in Endocrinology by Anil Bhansali Anuradha Aggarwal Girish Parthan & Yashpal Gogate

Author:Anil Bhansali, Anuradha Aggarwal, Girish Parthan & Yashpal Gogate
Language: eng
Format: epub
Publisher: Springer India, New Delhi

3. Why is pubarche not used to define the onset of normal puberty?

Reactivation of hypothalamic–pituitary–gonadal (HPG) axis is manifested by thelarche in girls and testicular enlargement in boys, and these are considered as first signs of puberty. Pubarche is a clinical manifestation of adrenarche and denotes the maturation of zona reticularis which is independent of reactivation of HPG-axis. Therefore, pubarche is not used to define the onset of normal puberty.

4. What is kisspeptin?

Kisspeptin is a neuropeptide secreted from the arcuate nucleus and anteroventral and periventricular (AVPV) nuclei of the hypothalamus. The arcuate nucleus comprises of KNDy (pronounced as “candy”) neurons which co-secrete kisspeptin (K), neurokinin B (N), and dynorphin (Dy), whereas AVPV nuclei comprise of Kiss-1 neurons, which secretes only kisspeptin. Both KNDy neurons and Kiss-1 neurons synapse with GnRH neurons. Kisspeptin acts on its receptor GPR-54, which is present on GnRH neurons in the hypothalamus. Kisspeptin signaling is involved in initiation of puberty, regulation of gonadotropin secretion by sex steroids, and preovulatory LH surge (Fig. 7.2).

Fig. 7.2“Kisspeptin-GnRH” axis

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.