In vitro effects of uncarboxylated osteocalcin on buffalo Leydig cell steroidogenesis.

Uncarboxylated osteocalcin (UcOCN), a bone derived circulating protein, has been demonstrated to influence steroidogenesis in testicular Leydig cells of murine and human species. However, the role of UcOCN in testosterone biosynthesis remains unexplored in domestic animals. The present study aimed to investigate the impact of UcOCN on the expressions of steroidogenic genes (HSD3ß1, HSD3ß6, CYP17A1, CYP11A1), testosterone production and GPRC6A receptor localization in buffalo Leydig cells. Leydig cells from the testes of adult Murrah buffalo were isolated, with an average cell count and viability after digestion and Percoll enrichment of 1.43 × 106 cells/g of testes and 78.5%, respectively. Immunophenotyping of Percoll-enriched cell suspension by flow cytometry showed populations of Leydig cells ranging between 69 and 73.9%. Immunostaining confirmed the presence of GPRC6A receptors and CYP11A1 positive Leydig cells. When these cells were cultured and incubated with varying levels of UcOCN (6, 12, 24, and 48 ng/ml) and LH, there was a significant (P < 0.01) increase in testosterone production and up-regulation (P < 0.05) of CYP11A1, CYP17A1, HSD3ß1 and HSD3ß6 gene expression. In summary, the present study underscored the effects of UcOCN on testosterone biosynthesis, expression of crucial steroidogenic genes and interaction with GPRC6A receptors in buffalo Leydig cells, emphasizing its potential implications in andrology.

Responsiveness of prepubertal crossbred bull calves to exogenous GnRH and its impact on reproductive hormones under tropical conditions.

This study investigated the age related variations in luteinizing hormone (LH), androstenedione, testosterone, and total estrogens response to exogenous gonadotropin-releasing hormone (GnRH) in Holstein-Friesian (HF) × Tharparkar bull calves. Fifteen bull calves were selected and, based on their age, were divided into Group I (14-16 months, n = 5), Group II (9-12 months, n = 5), and Group III (6-8 months, n = 5). All bull calves were administered with 10 µg of GnRH intramuscularly. Blood samples were collected at an interval of 30 min commencing 1 h prior to GnRH treatment until 4 h post-GnRH treatment and thereafter, at an interval of 1 h for the next 3 h. Endocrine response in terms of pretreatment values, peak values, area under curve, and time taken to attain peak values for LH, androstenedione, testosterone, and total estrogens was evaluated in all the bull calves. Significant differences were observed in pretreatment values, peak concentrations, and area under curve for androstenedione and testosterone between the groups; with response being higher in Group I bull calves. The results indicated that the HF × Tharparkar bull calves of 14 months age and above respond to exogenous GnRH by secreting significant amounts of testosterone.