Adavi H, Jafarzadeh Shirazi M R, Zamiri M J, Namavar M R, Tanideh N, Tamadon A. Effect of lactation on the expression of gonadotropin-inhibitory hormone in dorsomedial and paraventricular nuclei of the rat hypothalamus . Physiol Pharmacol 2011; 15 (2) :164-172
URL:
http://ppj.phypha.ir/article-1-716-en.html
Abstract: (12867 Views)
Introduction: Gonadotropin inhibitory hormone (GnIH) is believed to be an inhibitor of gonadotropin releasing
hormone (GnRH) secretion. The role of GnIH in lactational inhibition of gonadotropin secretion is not well known
therefore, the aim of the present study was to evaluate the effect of lactation on expression of GnIH in these nuclei of
lactating and non-lactating rats.
Methods: Ten postpartum rats of the Sprague-Dawley strain were randomly allotted into two groups. The number
of pups was adjusted to five pups per suckling female, while the control non-lactating rats were separated from their
pups immediately upon parturition. The lactating rats were allowed to suckle their pups for eight days. The number of
GnIH neurons in the dorsomedial (DMH) and paraventricular (PVN) nuclei was estimated using an
immunohistochemical method.
Results: The number of GnIH neurons in DMH (P=0.005) and PVN (P=0.001) of lactating rats were significantly
higher than those of the non-lactating rats. Moreover, fibers of GnIH neurons were observed in anteroventral
periventricular nucleus (AVPV) in lactating rats.
Conclusion: Lactation increased GnIH expression in DMH and PVN of the lactating rats, and thus may have a role
in inhibiting GnRH and subsequently LH secretion during the lactation period.