Objective To explore the possible mechanism of Bushen Zhuyun Formula（BZF

补肾助孕方） in treating luteal phase defect（LPD）. Methods A total of 40 female SD rats of childbearing age were randomly divided into normal group

model group

BZF group

H-7 group and H-7 plus BZF group

with eight rats in each group. Except for the normal group

rats were given mifepristone suspension to establish the LPD model. Starting from the fourth sexual cycle（Day 13）

BZF at a dose of 2.4 g/100 g was given by gavage in BZF group

while 0.005 mg H-7 was intraperitonealy injected into each rat in H-7 group at 16:00 on Day 13 and Day 17 and at 08:00 on Day 14 and Day 18; at the same time points

the rats in the H-7 plus BZF group were administered with same dose of drugs as the H-7 group and BZF group

and the rats in the model group and normal group were gavaged with 1.2 ml/100 g normal saline and intraperitonealy injected with 20μl normal saline per rat. At six hours after the last administration

the contents of luteinizing hormone（LH） and follicle stimulating hormone（FSH） in serum were detected by enzyme-linked immunosorbent assay（ELISA）

and FSH/LH was calculated; hematoxylin eosin（HE） staining was used to observe the pathological changes of ovarian tissue and the numbers of follicles and corpus luteum; the protein levels of pituitary tissue protein kinase C（PKC）

phosphorylated p38 mitogen activated protein kinases（p-p38 MAPK） and phosphorylated extracellular signal-regulated kinase 1/2（p-ERK1/2） were detected by Western blotting. Results Compared to those in the normal group

the atresia follicle in the ovarian tissue increased in the model group and H-7 plus BZF group; there was dysplasia of corpus luteum; the content of serum LH increased（P<0.05）; the numbers of ovarian follicles and corpus luteum

the content of serum FSH and FSH/LH ratio

and the protein levels of PKC

p-p38 MAPK and p-ERK1/2 in pituitary significantly increased（P<0.05）. Compared to those in the model group and H-7 plus BZF group

the atresia follicle in the ovarian tissue

the luteal cell dysplasia

and the content of serum FSH of rats in BZF group significantly decreased（P<0.05）; the numbers of ovarian follicles and corpus luteum

the content of serum FSH and the ratio of FSH/LH

as well as the protein levels of PKC

p-p38 MAPK and p-ERK1/2 in pituitary significantly increased（P<0.05）. Conclusion BZF can activate PKC/MAPK/ERK pathway in pituitary and promote the secretions of serum FSH

thereby improving the luteal function of LPD rats.