Short-term feed restriction decreases the systemic and intrafollicular concentrations of leptin and increases the vascularity of the preovulatory follicle in mares.

Theriogenology 73(9):1202 (2010) PMID 20226513

The objective of this study was to evaluate the effect of short-term feed restriction on characteristics of the preovulatory follicle and on concentrations of systemic hormones (leptin, follicle-stimulating hormone [FSH], luteinizing hormone [LH]) and follicular fluid hormones and growth factors (leptin, estradiol, inhibin-A, activin-A, free insulin-like growth factor-1 [IGF1], insulin-like growth factor binding protein 2 [IGFBP2], vascular endothelial growth factor [VEGF]). Mares were submitted to a short-term (48 h) feed restriction when the expected ovulatory follicle was > or =27 mm (Hour 0) or served as controls (n=8/group). No effect of short-term feed restriction was detected for systemic concentrations of FSH and LH and for intrafollicular concentrations of estradiol, activin-A, free IGF1, and IGFBP2. Restricted mares had decreased systemic concentrations of leptin at Hour 24 (approached significance) and at Hours 36 and 48 (P<0.04). Follicular fluid of restricted mares at Hour 48 had lower (P<0.02) concentration of leptin and a tendency (P<0.1) for greater concentrations of inhibin-A and VEGF. The percentage of wall of the preovulatory follicle with color-Doppler signals of blood flow at Hour 48 was greater (P<0.04) in the restricted group. Intrafollicular concentration of leptin (combined groups) was positively correlated with score for body condition (r=+0.60; P<0.002) and negatively correlated with the percentage of the follicle wall with blood-flow signals (r=-0.60; P<0.02). Our favored interpretation is that the preovulatory follicle seems to compensate for a nutritional deficiency by increasing the blood flow in the follicle wall. 2010 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.theriogenology.2009.11.032