Therapeutic hormones - Pharmaceutical Biotechnology: Concepts and Aapplications - page 320

• activin A β A β A

• activin AB β A β B

• activin B β B β B .

Inhibins and activins were initially identifi ed as gonadal-derived proteins capable of inhibiting
(inhibin) or stimulating (activin) pituitary FSH production (Figure 11.10). The major gonadal
sites of inhibin synthesis are the Sertoli cells (male) and granulosa cells (female). In addition to

Higher brain
centres

Higher brain
centres

testosterone

Hypothalamus Hypothalamus

LHRH

LHRH

FSH

Anterior Pituitary Anterior Pituitary

testosterone

inhibin FSH inhibin

LH

LH

FSH

Ovary

Testis

Theca cell

activin

Granulosa
cell

Corpus
luteum

Sertoli cell Leydig cell

Follicle

inhibin
activin
testosterone

Estrogen

Progesterone

Endometrium

CG

Embryo

Placenta

Female Male

Negative feedback

Positive feedback

Figure 11.10 Interrelationships between various hormones regulating reproductive function in the male
and female. Particular emphasis is placed upon the regulatory effect many have on the production levels of
additional reproductive hormones