Although it is well documented that leptin signals the body nutritional status to the brain, mechanisms of leptin regulation at the ovary are not well understood. This study was conducted to determine whether there was leptin and the receptor for leptin (LEPR) in cattle ovarian follicles and to investigate potential actions of leptin on follicular growth in vivo and on regulation of granulosa cell functions in vitro. There was leptin and LEPR in granulosa and theca cells of dominant and subordinate follicles, with greater immunostaining for leptin in granulosa cells of subordinate follicles. There was a lesser relative abundance of leptin receptor gene-related protein (LEPROT) and of the adiponectin receptors 1 (ADIPOR1) and 2 (ADIPOR2) mRNA transcripts in granulosa cells of subordinate than dominant follicles (P < 0.05). Intrafollicular injection of either 100 or 1000 ng/mL leptin did not affect the diameter and the growth of dominant follicles (P> 0.05). Supplementation of in vitro culture medium with different leptin concentations did not affect (P > 0.05) the relative abundance of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (HSD3B1), cytochrome P450 family 11 subfamily A member 1 (CYP11A1), signal transducer and activator of transcription 3 (STAT3) and X-linked inhibitor of apoptosis protein (XIAP) mRNA transcripts in granulosa cells. These findings indicate that leptin and LEPR are present in the follicular cells of cattle ovaries, but leptin apparently does not have essential functions in steroidogenesis and growth of dominant follicles.

尽管瘦素向大脑发出身体营养状况的信号已得到充分证明，但瘦素在卵巢中的调节机制尚不清楚。本研究旨在确定牛卵泡中是否存在瘦素和瘦素受体 (LEPR)，并研究瘦素对体内卵泡生长和体外颗粒细胞功能调节的潜在作用。优势和从属卵泡的颗粒和膜细胞中存在瘦素和LEPR，从属卵泡的颗粒细胞中瘦素的免疫染色更强。瘦素受体基因相关蛋白（LEPROT）和脂联素受体1（ADIPOR1）和2（ADIPOR2 ) mRNA 转录在从属卵泡的颗粒细胞中（P < 0.05）。卵泡内注射 100 或 1000 ng/mL 瘦素不影响优势卵泡的直径和生长（P > 0.05）。补充具有不同瘦素浓度的体外培养基不影响（P > 0.05）羟基-δ -5-类固醇脱氢酶、3β-和类固醇δ-异构酶1（HSD3B1）、细胞色素P450家族11亚家族A的相对丰度成员 1 ( CYP11A1 )、信号转导和转录激活因子 3 ( STAT3 ) 和 X 连锁凋亡蛋白抑制剂 ( XIAP)) 颗粒细胞中的 mRNA 转录物。这些发现表明瘦素和 LEPR 存在于牛卵巢的卵泡细胞中，但瘦素显然在类固醇生成和优势卵泡的生长中没有必要的功能。