Impact of growth hormone (GH) and follicle stimulating hormone (FSH) on in vitro canine preantral follicle development and estradiol production

ObjectiveEvaluate the effect of different concentrations of growth hormone (GH) on the in vitro development of domestic dog (Canis lupus familiaris) preantral follicles in the presence or absence of follicle stimulating hormone (FSH).MethodsSecondary preantral follicles, isolated by microdissection, were cultured in a medium composed of αMEM with bovine serum albumin (BSA), glutamine, hypoxanthine, insulin, transferrin, selenium and ascorbic acid (αMEM+-control) added at different concentrations of GH (GH10 ng/ml or GH50 ng/ml) and FSH (GH10 + FSH, GH50 + FSH). Follicle development was evaluated based on the percentage of intact follicles, antrum formation, follicular diameter, follicular viability using fluorescent markers and estradiol production.ResultsGH50 was the only treatment that maintained the same percentage of normal morphologically follicles from day 0 to day 18 of culture (P < 0.05). For all treatments, except the control, follicles were viable throughout the 18 days of culture (P < 0.05). GH50 supplemented with FSH (GH50 + FSH) resulted in the highest average follicular diameter (P < 0.05) from day 12 to 18. Follicles from both the control and the GH50 + FSH treatment groups actively and increasingly secreted estradiol from day 6 to 18 of culture (P < 0.05).ConclusionsOur study demonstrates that GH benefits the maintenance of follicular morphology in a dose-dependent manner and, in association with FSH, stimulates in vitro follicular growth and estradiol production.