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ENDOCRINE PHYSIOLOGY

Puberty

Highcr

cerebral

centers

"trigger"

adeno-

hy|H>phv«s

Higher

cerebral

centers

"togger"

adeno

hypophysis

recession

begins

Acne appears

Prolactin

Prolaclir

Axillary hair

Breasts

develop

enlarges -

Menstruation begins \    ,

Yaginal

epilhelium

cornifies

Epiphysial hastened ^

•    Acne appe

•    Facial hair appears

Piluitary gonado-tropins increased FSH-

Adrenal

androgens

increased

Adrenal

cortices

Relicular <?one enlarges

Estrogen

increased

■ AfTH

Adrenal

cortices

Adrenal

androgens

increasedj

Musculature

develops

Larynx

enlarges

(voice

deepens)

Ovaries

Keticular zonę enlarges Testes

Estrogen

pmduced,

Progesteronc i ' 'JpK; produced \40j

I II acts on theca cells to stimulate androgen production and on gran-ulosa cells lo stimulate progester-one production. FSH acts on graiv ulosa cells to stimulate production of estrogens from androgens

Testosterone

increased

LH acts on interstitial Leydig cells lo stimulate testosterone production. FSII with testosterone acts on Sertoli cells to stimulate spermatogenesis

Axillary hair appeais

Sonie breast enlargement may occur

Pubie hair appears • Penis,

prostatę,

and

seminal

vesides

enlarge

• Epiphysial union hastened

Figurę 8.25 Puberty_

One to iwo years before puberty, adrenal androgen levels increase (adrenarchel. These adrenal androgens are responsible. in both sexes, for the early development of pubie and axillary liair and increased growth. At puberty, the hypothalamus increases the frequency and amount of gonadotropin-releasing hormone (GnRHl released. GnRH in tum stimulates the release of luteinizing hormone (LH) and follicłe-slimulating honnone (FSH) by the anterior pituitary. In the małe, LH acts on the interstitial Leydig cells of the testes to stimulate the production of testosterone. FSH together with testosterone acts on the Sertoli cells of the testes, which are important for support and devdopment of the spermatozoa. In the female, LH acts on l>oth the theca and granulosa cells of the ovary. In response to LH. the theca cells produi t-androgens, which are then converted to estrogens by the granulosa cells. LH acts on the granulosa cells to stimulate progesteronc produc tion. FSH acts on the granulosa cells to stimulate the production of estrogens from androgens.

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