In vitro effect of leptin on anterior pituitary cells LH secretory activity during early pregnancy in pig

Abstract

Leptin modulates reproductive activity but its potential influence on LH secretion from anterior pituitary (AP) cells during implantation period in pigs (days 14-16 of pregnancy) remained unexplored. This study focused on determination whether leptin affects basal and GnRH-induced LH secretion and intracellular accumulation and whether leptin receptor (OB-Rb) mRNA is expressed in the AP gland during implantation in pigs. Four individual AP glands were developed into separate primary cultures. 2x10 5 cells/ml were preincubated (72 h) and next, for 3.5 h, experimentally treated with GnRH (100 ng/ml), leptin (10 -11 , 10 -9, 10 -7, 10 -6 M) alone, or given in respective combinations with GnRH. In the AP gland, OB-Rb mRNA expression was determined by real-time PCR method. Leptin activated LH secretion and its concentration-dependent effect was observed as stimulation shown in a full range tested (culture 1) and exhibited only at 10 -6 M (culture 2). A pooled data analysis revealed that basal LH secretion increased at 10 -9 , 10 -7 and 10 -6 M, but GnRH-induced LH release decreased at 10 -6 M. Leptin down-regulated GnRH-induced LH secretion in all cultures, but only culture 3 exhibited sensitivity for all concentrations tested. Basal LH accumulation was activated in culture 1 (at 10 -11 M) and inhibited in culture 4 (at 10 -9 M). In the presence of GnRH leptin up-regulated LH accumulation with individual culture leptin-sensitivity (culture 1-3), while down-regulated LH accumulation in culture 4. Obtained data indicate that OB-Rb mRNA is expressed in the AP gland and leptin alone and in combination with GnRH specifically modulates LH activity during early pregnancy in pigs.

The positive influence of leptin in mature corpus luteum function of pregnant sows

“…The present study, we found that leptin dose-dependently accelerated the release and mRNA expression of LH in luteal cells. The results are in accordance with the reports on pituitary cells, which demonstrated that leptin directly promoted gonadotropin release [62][63][64]. Results obtained from trophoblasts cells suggested that leptin stimulated hCG secretion [65,66].…”

Expression of Apelin and Apelin Receptor Protein in the Hypothalamo-Pituitary-Ovarian Axis during the Estrous Cycle of Mice

“…The pituitary (1 pituitary per tube) was cultured in 500 μL of medium in a humidified atmosphere with 95% air and 5% CO 2 for 24 h at 37°C. The pituitary was divided into four groups: (i) control group (CON), cultured only in media, (ii) GnRH group, cultured in the presence of GnRH agonist at a dose of 100 ng/mL [35], (iii) GnRH+AP group, cultured in the presence of GnRH agonist and APLN-13 at a dose of 1 μg/mL [36], and (iv) GnRH+ML group, cultured in the presence of GnRH agonist and APLN inhibitor ML221 at a dose of 50 µ m [37]. After 24 h, media was collected for ELISA.…”

Analisis Genetik Gen Leptin Berdasarkan Sekuen DNA GenBank dan Asosiasinya dengan Reproduksi Ternak Babi

“…Dalam sistem syaraf pusat, hipotalamus adalah target utama leptin yang akan berikatan dengan neuron Gonadotropin (GnRH) untuk menstimulasi pelepasan GnRH. Leptin yang dihasilkan oleh jaringan lemak adiposa akan berikatan dengan GnRH untuk menstimulasi produksi FSH dan LH di hipofisa anterior (Slawrys & Gajewska, 2017). Hormon FSH dan LH mengatur ovulasi dan folikulogenesis.…”

“…Peningkatan konsentrasi leptin diasosiasikan dengan onset pubertas pada beberapa babi dara (Rybska et al, 2018) (Takle et al, 2017). Melalui mekanisme terpusat di otak bagian hipotalamus, hormon leptin ini berfungsi menghubungkan antara jaringan adiposa dan sistem reproduksi dalam menyediakan dan mengatur kebutuhan energi untuk reproduksi dan kehamilan (Slawrys & Gajewska, 2017); Lents et al, 2020). Hewan yang mengalami insufisiensi hormon leptin akan mengalami keterlambatan dewasa kelamin, infertilitas disertai potensi obesitas.…”