diff --git a/grpc.go b/grpc.go
index ebdbed5..7a8aacf 100644
--- a/grpc.go
+++ b/grpc.go
@@ -291,7 +291,7 @@ func (g *grpcClient) Options() client.Options {
 }
 
 func (g *grpcClient) NewMessage(topic string, msg interface{}, opts ...client.MessageOption) client.Message {
-	return newGRPCPublication(topic, msg, "application/octet-stream")
+	return newGRPCPublication(topic, msg, g.opts.ContentType, opts...)
 }
 
 func (g *grpcClient) NewRequest(service, method string, req interface{}, reqOpts ...client.RequestOption) client.Request {