Leptin in the bovine corpus luteum: Receptor expression and effects on progesterone production

Abstract

In cattle, leptin has been implicated in the control of ovarian function and has been shown to modulate steroid production by theca and granulosa cells in a number of species. However, a direct effect of leptin on bovine luteal function has not been demonstrated. This study was conducted to determine if the leptin receptor (OB-R) is expressed in the bovine corpus luteum (CL), and to examine the effects of leptin on progesterone production by dispersed luteal cells in vitro. RT-PCR was used to detect the presence of OB-R and, more specifically, the long, biologically active isoform (OB-Rb), in CL, collected on days 2-18 of the oestrous cycle (n=18). The effects of leptin on progesterone production were investigated in dispersed luteal cells prepared from CL collected on days 5 and 8 (n=14) of the cycle. The dispersed luteal cells were cultured for 24 hr with recombinant human leptin and/or LR3-IGF-1 and/or LH. OB-Rs, in particular, OB-Rb, were expressed in the CL at all stages of development. Progesterone production by luteal cells was increased (P<0.001) by treatment with LH (10 ng/ml) but treatment with leptin alone had no effect. However, in the presence of IGF-1 (100 ng/ml), leptin (10 ng/ml) caused a significant (P<0.005) increase in progesterone production. In conclusion, we have shown that the leptin receptor is expressed in the bovine CL and have demonstrated a modulatory effect of leptin on luteal progesterone production in vitro.

Opposing Roles of Leptin and Ghrelin in the Equine Corpus Luteum Regulation: AnIn VitroStudy

“…For instance, the first adipokine to be described, LEP, has been recurrently associated with food intake regulation, body weight, and energy balance [35]; nonetheless, LEP was also shown to regulate ovarian function, in particular the CL in human [36], porcine [26], and bovine [27]. Moreover, the local auto- and paracrine role of factors such as LEP and GHR in luteal function modulation is not fully understood.…”

“…This domain is responsible for the majority of the biological effects of LEP [22]. The expression of ovarian LEPR and its involvement on ovarian function were demonstrated in human [23], mouse [24], rat [25], porcine [26], and bovine [27]. …”

Associations between lipid metabolism and fertility in the dairy cow

“…This supports the importance of a direct role of leptin on reproduction. In particular, leptin treatments in vitro can contribute to the regulation of ovarian steroidogenesis, showing synergistic actions with IGF1 (Spicer 2001;Nicklin et al 2007). Leptin can also influence oocyte maturation and fertilisation rate (Boelhauve et al 2005) and gonadotrophin secretion, although in ruminants this latter action only seems to be important during very severe undernutrition (Zieba et al 2005).…”

The effect of nutrition and metabolic status on the development of follicles, oocytes and embryos in ruminants

“…In the bovine species, leptin and its receptor transcripts are present in the corpus luteum and their expression decrease during luteal regression (Sarkar et al, 2010). Leptin increased in vitro IGF-I-induced luteal progesterone production (Nicklin et al, 2007).…”