Induces cartilage and bone formation. May be the osteoinductive factor responsible for the phenomenon of epithelial osteogenesis. Plays a role in calcium regulation and bone homeostasis (By similarity). Involved in the generation of primordial germ cells; this function involves Bmp4 in a synergistic manner though separate receptor complexes seem to be involved. Required for the initiation and maintenance of spermatogenesis. Signaling protein involved in regulation of thermogenesis and energy balance. Proposed to increase the peripheral response of brown adipose tissue (BAT) to adrenergic stimulation while acting centrally in the hypothalamus to increase sympathetic output to BAT. Homodimer; disulfide-linked. Expressed in testis. Expressed in decidual cells of the uterus and in trophoblast cells of the labyrinthine region of the placenta and in the inner root sheath of hair follicles of early postnatal skin. Expressed in the extraembryonic ectoderm in pregastrula and gastrula stage mouse embryos. Expressed in brown adipose tissue and brain. Expressed during specific stages of spermatogenesis, with highest levels in stage 6-8 round spermatids after 3 weeks of age. By feeding with high-fat diet and cold exposure. By beta-3-adrenergic receptor activation and thyroid hormone treatment. Absence of primordial germ cells, short or missing allantois. Belongs to the TGF-beta family.